Concrete Mix Ratio Calculator (1:2:3 / 1:1.5:3 etc.)

Weigh the fertilizer dropped over a small test area and convert it to a rate per 1,000 sqft (or 100 m²) to dial in your broadcast spreader setting.

Estimate a sustainable stocking rate and grazing days from pasture area, forage yield per area and each animal unit's intake.

Use the nursery rule of gallons per inch of trunk caliper to get the recommended watering volume for a newly planted tree.

Enter the combined flow of all heads in a zone and the area they cover to get the precipitation rate (mm/hr or in/hr) and the run time needed for a target watering depth.

Hong Kong service charge, extra tipping and bill-splitting in one tool.

Estimate monthly bill using the latest CLP / HKE tariff.

Estimate the fuel cost of a trip from distance, vehicle consumption and fuel price (one-way or round-trip).

Enter the bill, service charge, tip and party size to get each person’s share — then round each share up to the nearest $1 / $5 / $10 / $20 / $50 to make cash collection painless.

Enter the original price and a percent off (or fixed amount off) to see the final price, money saved and effective discount.

Convert between cups, tablespoons, teaspoons, millilitres, ounces and grams — for following overseas recipes or halving / doubling portions.

Compare two products by price-per-unit (per g, kg, ml, L or each). Enter price + amount + unit for each — see which is cheaper and by how much.

Convert hourly wage to monthly / annual salary or back — with customisable hours per week and weeks worked per year. Works for part-time, freelance and salaried jobs.

Estimate a dog's human-equivalent age from its actual age and size (small / medium / large / giant), with both the classic "×7" rule and modern research curves side by side.

How many people, how hungry, and how many slices per pizza? Get the exact number of pizzas to order — no leftovers, no shortages.

Enter room dimensions and tile size to estimate the number of tiles needed (including a configurable waste allowance) — for floor or wall jobs.

From room length, width and height, door and window area, paint coverage per litre and the number of coats, estimate how many litres of paint you need.

Pick a brew method (pour-over, French press, cold brew or espresso) and a desired output, and get the exact coffee dose and water weight to match the recommended ratio.

Enter the room size, roll dimensions and pattern repeat to get the number of wallpaper rolls to order (with pattern-match waste included).

Enter cigarettes per day, price per pack and years smoked — see your total spend and how much you could save by quitting.

Convert any roof rise / run into the X-in-12 pitch notation used by builders, plus the slope angle in degrees, slope percentage and the rafter-length multiplier.

Enter slab length, width and thickness with a waste factor and get the concrete volume (m³, yd³, ft³) plus the approximate number of 25 kg, 40 kg or 80 lb pre-mix bags required.

Enter total rise and a target riser height to get the number of risers, actual riser height, tread depth, stringer length, pitch and a side-by-side compliance check against the IRC, IBC and UK Approved Document K.

Enter room area, ceiling height, sun exposure, occupants and climate to find the recommended air-conditioner BTU rating / horsepower.

Enter your wedding date to see the anniversary number, days until the next one, and the traditional / modern gift theme (paper, silver, gold…).

Convert oven temperatures between Celsius, Fahrenheit and British gas marks, with descriptive labels (slow / moderate / hot / very hot).

Enter original servings and desired servings to scale every ingredient proportionally, with friendly rounding to common cookware-sized amounts.

Enter your cat's real age to estimate the human-equivalent age using the standard veterinary formula and see the matching life stage (kitten, adult, senior, geriatric).

Enter price, expected number of uses and upkeep cost to compute true cost per use — see whether that item is really worth it.

Estimate hiking time with the classic Naismith's Rule (1 h per 5 km plus 1 h per 600 m of ascent), with optional descent and rest-time corrections.

Enter power (W / kW / hp) and weight (kg / lb) to instantly compute W/kg, hp/kg and hp/lb ratios with cyclist and car performance bands.

Enter battery capacity (kWh), charger power (kW) and the start / target state of charge to estimate how long an EV charging session takes, with adjustments for charging efficiency and the constant-current → constant-voltage taper above 80 %.

Enter the original gravity (OG) and final gravity (FG) of a beer or wine ferment and the calculator returns the standard homebrewing ABV estimate ABV ≈ (OG − FG) × 131.25, plus apparent attenuation and a calorie estimate.

Enter the area and target depth to compute the volume of mulch, soil or gravel needed (in litres, m³ and cubic yards), and estimate bag count and total cost.

Enter the dimensions of your tank — rectangular, cylindrical or bow-front — to get the water volume in litres, US gallons, UK gallons and water weight, with a fill-percentage adjustment for substrate and décor.

Enter flour weight and target hydration to get water, salt and yeast quantities via baker's percentage — with Neapolitan, NY and Sicilian style presets.

Enter an original price and two discounts applied in sequence (e.g. "30% off then an extra 10%") — the tool returns the final price, the equivalent single discount and the savings, sidestepping the common mistake of simply adding the percentages.

Enter a TV or monitor diagonal and an aspect ratio (e.g. 16:9, 21:9) and the tool returns the actual width, height and area in both inches and centimetres — handy for furniture planning, wall-mount fit and seeing why a "55-inch" is so much bigger than a "50-inch" in area.

Enter great-circle distance (km / mi / nm), cabin class and segment type (domestic / short / long-haul); the tool applies DEFRA 2024 emission factors to estimate per-passenger CO₂-equivalent kilograms, total trip emissions and tree-month offsets — the standard checklist for business-travel reporting, personal carbon budgets and offset-purchase decisions.

Enter an amount and a VAT / GST rate; the tool computes both directions — adding tax to a net price, and extracting the tax already embedded in a gross price. Works for any country that uses VAT / GST / IVA / TVA (UK 20%, EU 17–27%, AU & SG GST, India GST, etc.).

Enter daily energy use (kWh), peak sun hours, panel wattage and overall system efficiency; the tool returns the required array size in kW and the number of panels needed — a starter sizing tool for rooftop PV, off-grid cabins and RV / van conversions.

Enter room L × W × H and target air changes per hour; the tool returns the required ventilation airflow in CFM, m³/h and L/s. Built-in ASHRAE 62.1 presets (bedroom, kitchen, conference room, gym, etc.) make it easy to size extract fans, supply diffusers and HEPA purifiers.

Enter chainring teeth, sprocket (cog) teeth and wheel size (700C, 26", 29er, etc.); the tool returns classic gear inches, metres of development and speed for any cadence — cyclists' go-to comparison for climbing-friendly vs. high-speed gear setups.

Enter the hang time of a jump (seconds); the tool applies the free-fall formula h = ⅛ g t² to give the vertical jump height (cm), and also reports the take-off velocity and apex time — used in basketball, volleyball, plyometric training and fitness testing.

Enter the number of teams or players; the tool returns total matches and rounds for single-elimination (N − 1), double-elimination, single round-robin (N·(N−1)/2) and double round-robin formats, plus the number of byes in the knockout bracket — useful for tournament scheduling in sports, board-game leagues and esports.

Enter total swim time and distance (metres or yards); the tool returns pace per 100 m (or 100 yd) and predicts completion time for any target distance — essential for pool training, triathlon and masters racing.

Enter two players' Elo ratings (chess, online games or any Elo-style ladder); the tool uses the FIDE formula E = 1 ⁄ (1 + 10^((Rb − Ra) ⁄ 400)) to return each player's expected score and the rating change after a chosen result and K-factor — used by chess players, esports competitors and Glicko/USCF tournament preparation.

Enter total fence length, spacing between posts and number of gates; the tool returns post count (line + corner + end), rail count and panel sections — the classic "fence-post problem" reduced to one click for homeowners, farms and contractors estimating materials.

Enter room length, width and height, opening (door / window) area, sheet size (4×8, 4×10 or 4×12 ft) and waste factor; the tool returns sheets needed, total square footage and estimated screws, joint tape and joint compound — a quoting tool for DIY remodels and drywall contractors.

Enter the length, width and thickness of a driveway or road; the tool uses the density of hot-mix asphalt (~2.4 t/m³) to return tonnage and converts inch/foot inputs to metric tonnes — a quoting tool for DIY homeowners, HOAs and paving contractors.

Enter pet weight, species (dog or cat), life stage and activity level; the tool uses the NRC Resting / Maintenance Energy Requirement formulas to compute daily calorie needs and the matching dry-food portion (grams/day) — the standard tool for pet owners.

Recipe calls for pan A but you only have pan B? Enter both pans (round / square / rectangular) and the tool returns the ingredient scale factor by volume ratio plus a suggested bake-time adjustment — works across all common pan shapes.

Enter screen diagonal (inches) and resolution (1080p / 4K / 8K); the tool returns optimal and maximum viewing distance based on SMPTE 30°, THX 36° field-of-view recommendations and human visual acuity — the standard tool for sizing a new TV or arranging your couch.

Enter the gasoline volume and the desired ratio (25:1, 32:1, 40:1, 50:1, etc.); the tool returns the exact two-stroke oil quantity in mL and US fl oz — works for chainsaws, weed trimmers, outboard motors, two-stroke motorbikes, leaf blowers and any other two-stroke engine.

Enter room length, width (m or ft) and ceiling height; the tool consults the ASHRAE / ENERGY STAR ceiling-fan sizing guide to recommend a blade span (29″–72″) and a minimum CFM (airflow) rating, and flags whether a downrod is needed to keep the 8 ft sweet-spot height.

Enter a server's total tips for the shift and the percentage tipped out to each support role (bartender, busser, host, kitchen); the tool returns the amount sent to each role and the server's take-home tip. The standard "tip out" workflow used in US, Canadian and Australian restaurants.

Enter the counts of Promoters (9–10), Passives (7–8) and Detractors (0–6); the tool returns NPS = %Promoters − %Detractors on a −100 to +100 scale. The de-facto standard customer-loyalty and product-experience metric for SaaS and retail.

Enter the post engagements (likes + comments + shares) and the denominator (followers, reach or impressions); the tool returns engagement rate by all three bases. Standard benchmark in influencer marketing, brand-KOL evaluation and ad-campaign reporting.

Enter the semitone gap between two notes (or two frequencies directly); the tool returns the frequency ratio via 2^(n⁄12) and the cents gap via 1200·log₂(f₂⁄f₁). The standard tool for music theory, instrument tuning and harmonic analysis.

Enter the horizontal distance covered and the vertical altitude lost; the tool returns the glide ratio (L/D), the glide angle and the equivalent lift-to-drag ratio. The fundamental performance metric for paragliders, sailplanes, unpowered aircraft and skydivers.

Enter the catchment roof area, annual rainfall (mm) and surface runoff coefficient; the tool returns harvestable rainwater per year (litres / US gallons), monthly average and equivalent irrigation days. The first-pass sizing tool for residential rain barrels and garden irrigation systems.

Enter flour weight and water / salt / yeast / fat percentages (as % of flour weight); the tool returns each ingredient amount and the dough hydration using the standard baker's percentage system — the universal way bakers scale bread recipes up or down.

Enter lawn area, the NPK label numbers on the fertilizer bag (e.g. 10-10-10) and the target nitrogen rate (lb N per 1000 ft² or g N per m²); the tool returns how much fertilizer to apply and the actual N / P / K delivered — standard for lawn care, gardening and small-farm agronomy.

Enter your straight ladder length and the height where it touches the wall; the tool returns the required base distance from the wall, the angle with the ground, and checks them against the OSHA / EN 131 "4-to-1" rule (1 unit of base for every 4 units of working height, ≈ 75.5°) — handy for home maintenance, painting and window cleaning.

Enter current temperature, current tire gauge pressure and target / future temperature; the tool returns the adjusted gauge pressure via Gay-Lussac's gas law — useful for winter inflation, long-distance driving and bicycle pressure under temperature swings.

Enter water weight and target salt % by weight to get grams of salt — or back-compute the % from existing salt + water. Common in pickling, lacto-fermentation, sous-vide brining; includes the standard 2 % / 3.5 % / 5 % recipe reference table.

Enter the tank or pool volume (L, m³, gal) and the inflow rate (L/min, GPM, m³/h …); the tool gives the fill time. Useful for pools, ponds, aquariums and water tanks.

Enter the A-weighted sound level (dBA); the tool returns the maximum daily safe exposure time using both the NIOSH (3 dB exchange) and OSHA (5 dB exchange) rules — relevant to concerts, construction sites, headphone listening and factory floors. Includes a reference table of common noise levels.

Enter the price and pack size of two products (mix units freely — g / kg / mL / L / pcs); the tool computes price-per-unit, flags the cheaper option, shows percentage savings and a normalised per-100 g / per-100 mL comparison.

Enter your target barbell total weight, the empty bar weight and the plates available in your gym (kg or lb); the tool uses a greedy decomposition to list the plates per side and flags any remainder that can't be matched.

Enter the vertical rise and horizontal run of a roof slope; the tool returns the pitch as a percent, degrees, the North-American X-in-12 ratio, and the rafter (hypotenuse) length via the Pythagorean theorem.

Enter the tank water volume (litres / US or imperial gallons), target water temperature and the coldest expected room temperature; the tool uses W ≈ 0.25 × V_L × ΔT (matching the Eheim Jager / Marina / Hagen sizing charts) to suggest a wattage, the closest commercial heater size and when to split into two heaters.

Enter the food thickness (mm), shape (slab / cylinder / sphere), type and bath / initial temperature; the tool applies Baldwin's heat-diffusion equations to estimate the time for the core to reach the bath (within 0.5 °C, the Baldwin standard) — sous-vide time depends on thickness, not weight.

Enter the vertical rise; the tool applies the widely-adopted 1:12 maximum slope (US ADA, ISO 21542, UK Approved Doc M, Singapore BCA) to give the minimum ramp length, and lists the per-9 m landing rule, handrail requirements and other code-compliance checks.

Enter the length, width and depth of a raised garden bed (cm or in); the tool returns the soil volume needed in litres, cubic feet and cubic yards, and converts that into the number of bags at common retail sizes (20 L, 40 L, 50 L, 1.5 cu ft, 2 cu ft) so you can buy the right amount from the garden centre.

Enter annual mileage, fuel economy, insurance, maintenance, depreciation, parking and loan interest; the tool returns the true cost per mile (and per km) so you can compare owning a car to ride-share, public transit or short-term rental.

Enter the bed length × width (m or ft), the in-row spacing and the row spacing; the tool computes the number of plants for both square-grid and triangular (offset) layouts plus the effective planting area — handy before ordering seedlings or seeds.

Enter the roast type (beef, pork, lamb, chicken, turkey), weight (kg or lb), desired doneness (rare/medium/well) and oven temperature; the tool consults the USDA / British Beef & Lamb published "minutes-per-pound" tables to give the suggested cooking time, plus pre-heat, rest and core-temperature guidance.

Enter rider + bike weight, speed, gradient (%), aerodynamic CdA, rolling resistance Crr and headwind; the tool sums the three drag components (gravity, aero, rolling) to give the power (watts) needed to hold that speed — useful for FTP comparison, climb pacing and gear-upgrade decisions.

Enter the pool volume (L or US gal), current free-chlorine ppm and target ppm; the tool returns the dose of liquid sodium hypochlorite (bleach) or calcium hypochlorite (trichlor) needed.

Enter a conventional oven temperature (°C or °F) and time; the tool applies the standard fan-oven rules (drop ~20 °C / 25 °F, multiply time by ~0.80) to give the convection setting — and works in reverse, too.

Enter each ingredient (spirits, liqueurs, syrup, juice, water) by volume (mL) and ABV (%); the tool adds the standard stir or shake dilution and returns the finished drink's total volume, final ABV and the number of standard drinks.

Enter the wall length × height, brick size (UK standard 215 × 102.5 × 65 mm, metric 240 × 115 × 71 mm or custom), mortar joint thickness (mm), the area of openings to subtract and a wastage factor; the tool returns the total bricks needed, mortar volume (m³) and a recommended safety surplus.

Enter the fridge's rated wattage (W) or the nameplate kWh/year, the actual duty cycle (compressor-on fraction, typically 30–50 %) and your electricity tariff; the tool returns the yearly kWh, cost and CO₂ emissions — useful for comparing replacement models against your current one.

Enter the wall length (ft or m) and the on-centre stud spacing (16 in, 19.2 in, 24 in or custom); the tool returns the required stud count including end studs, extra king / jack studs at openings, plus the total linear footage / metres of lumber for budgeting and ordering.

Pick a tea type (green, white, oolong, black, pu-erh, herbal, Earl Grey, matcha, etc.) and the tool shows the recommended water temperature range (°C / °F), first-steep time (seconds), number of re-steeps and per-steep extension — a handy reference for café training and home brewing.

Enter the pedalling cadence (RPM), front / rear sprocket teeth (chainring / cog) and wheel size (700×25c, 26 inch, etc.); the tool applies speed = cadence × (chainring / cog) × wheel_circumference to give distance per minute (m/min), km/h, mph and the gain ratio per pedal stroke — useful for picking a gear and pacing training rides.

Enter the lawn area, mower cutting width, walking/driving speed and pass overlap; the tool returns the pure mowing time plus a turning and setup buffer — useful for weekend yard planning or quoting a landscaping job.

Enter the largest chainring, largest rear sprocket and chainstay length; the tool applies the Park Tool formula L = 2·C + (F/4 + R/4 + 1) to give the required chain length in inches and links — useful for replacing the drivetrain, swapping a cassette or sizing a new chain after a break.

Enter the hub flange radius, flange spacing, rim ERD and cross pattern; the tool applies L = √(d² + r² + R² − 2·r·R·cos(α)) − D/2 to give the spoke length per side — useful for DIY wheel-building and spoke purchasing.

Enter your swatch gauge (stitches per 10 cm and rows per 10 cm) and the finished width and height you want; the tool gives the cast-on stitch count and total rows — avoiding the classic "finished sweater is the wrong size" problem.

Enter the gross trailer weight (GTW), target tongue-weight ratio (10–15 % for conventional, 20–25 % for fifth-wheel) and the measured tongue weight; the tool checks whether you are inside the safe band and suggests how to redistribute the load — preventing highway sway and fishtailing.

Enter your bet size, spins/hands per hour and house-edge percentage (or slot RTP); the tool returns the theoretical expected loss per hour, per session and per year — a sober budgeting tool for slot, roulette, blackjack and baccarat players setting bankroll and stop-loss limits.

Enter your mouse DPI, in-game sensitivity and yaw (degrees per count, default 0.022 for Source-engine games); get eDPI = DPI × sens and the cm / inches required to spin a full 360° — the tool every FPS player uses when migrating between games or picking a mousepad size.

Pick a pool shape (rectangle, round, oval, kidney) and enter the dimensions and average depth; the tool applies the appropriate geometric formula to give the water volume in m³, litres, US gallons and cubic feet — useful for chlorine dosing, heater sizing and water-bill estimates.

Enter two sRGB (or direct Lab) colours; the tool converts to CIE Lab and returns ΔE*ab = √(ΔL² + Δa² + Δb²) with a perceptual band (< 1: imperceptible; 1–2: visible on inspection; 2–10: clearly different; > 10: opposite colours) — the standard metric for print, brand-colour QA, photography and UI palette work.

Enter total characters typed, time elapsed and number of errors; the tool applies the industry-standard 1 word = 5 characters convention to return Gross WPM = (chars / 5) / minutes, Net WPM = Gross − (errors / minutes) and accuracy % — the standard typing-test metric used in classrooms, hiring, transcription and call-centre training.

Enter base hourly rate, regular hours, overtime hours and multiplier (1.5×, 2× or custom) — the tool returns regular pay, overtime pay and gross total, extrapolated weekly / biweekly / monthly. Works for the US FLSA, UK union and Canadian provincial frameworks.

Enter the nightly room rate, occupancy tax %, per-night resort / city fee and number of nights — the tool returns the pre-tax subtotal, taxes, fees, grand total and per-person share. Essential for comparing booking quotes and filing business-trip expenses.

Enter cake shape (round / square / rectangular) and size (diameter or side in inches or cm); the tool applies the Wilton industry-standard cut to return "wedding" (small), "party" (medium) and "generous" (large) servings — invaluable for weddings, birthday parties and event catering.

Enter the contractual annual leave entitlement, join date and (optionally) leave date — the tool returns the pro-rated leave for the part-year, by months or by calendar days. A universal framework that fits any local labour law or company policy.

Enter the package length × width × height and the actual weight, pick a carrier divisor (UPS / FedEx / DHL / international), and the tool returns the dimensional weight (DIM), the chargeable weight (max of actual vs DIM) and density — the standard way every major courier prices a parcel.

Enter the total yarn length required by your pattern (yards or metres) and the length per skein; the tool returns the number of skeins to buy with a chosen safety margin (5 %/10 %/15 %), the leftover yarn and total cost — the must-do check before walking into a yarn shop.

Enter how many pieces you need, each piece's length × width and your fabric width (45"/54"/60" or custom); using a one-way single-cut layout the tool returns required yardage (yards / metres) with adjustable shrinkage and pattern-match margin, and estimates total fabric cost — the standard pre-shop check for sewing, home décor, cosplay and curtain projects.

Enter two hex colours (#RRGGBB) and a blend ratio t ∈ [0, 1]; the tool returns the linear-RGB interpolation (1 − t)·A + t·B for the midpoint, plus a 5-stop gradient preview — handy for UI palette design, gradients and brand-colour transitions.

Enter your subscriptions (Netflix, Spotify, cloud storage, SaaS, etc.) with their billing cycles (weekly / monthly / quarterly / annual / biennial); the tool sums the monthly, annual and 5- / 10-year cumulative cost — the standard tool for surfacing how much those small recurring fees actually take out of your wallet, and a starting point for cancelling what you do not use.

Enter an original runtime and a playback speed; the tool returns the actual elapsed listening / viewing time, the minutes saved, and a full comparison table for 1.25× / 1.5× / 1.75× / 2× / 3× — the everyday helper for students speeding through lecture replays, professionals scrubbing meeting recordings and podcast listeners.

Enter each housemate or partner's income and the total bill to be shared (rent, utilities, household budget); the tool prorates the share by income so the higher-earner pays proportionally more — the standard fix for the "we earn very different amounts so we shouldn't split 50/50" problem, fairer than flat splitting.

Enter egg size (S/M/L/XL), starting temperature (fridge-cold or room temperature) and desired doneness (soft, medium, hard); the tool applies the Williams egg heat-conduction model to return boil-time minutes, so you stop guessing and stop overcooking.

Enter total rider + bike weight, tire width (mm) and front / rear load split; the tool applies the Frank Berto "15 % tire drop" model to return recommended PSI, so you avoid both over-inflation (harsh ride, less grip) and under-inflation (pinch-flat risk).

Enter the usable shelf length (cm) and the dominant book type (mass-market, trade paperback, hardcover, magazine, coffee-table); the tool applies publisher-average spine widths to estimate the number of volumes that fit and shows a mixed-type running total.

Enter window or track width, desired fullness factor (1.5×–3×), number of panels and side hem; the tool returns the finished width, cut width per panel and total fabric width to order — essential for sewing, custom-drapery ordering and fabric-bolt purchases.

Enter your singing key (and optionally a chord-shape key); the tool returns the required capo fret (0–11) and lists all 12 alternative positions — perfect for shape-based guitarists who need to drop or lift a song into their vocal range.

Frozen food often lists "1100 W microwave 90 s" — but how long do you cook it in a 700 W microwave? Enter the source wattage, the package time and your actual microwave wattage; the tool applies the inverse-proportion formula and adds a 10 % safety buffer for under-cooking.

Enter cartridge cost, the ISO/IEC-standard page yield (mono / colour separately), paper cost per sheet and your monthly print volume; the tool returns the true cost per page and annual cost — the key metric for comparing "cheap printer, expensive ink" vs "expensive printer, cheap ink" over the long term.

Enter one-way distance, fuel / electricity rate, vehicle economy, parking and toll fees and one-way transit fare; the tool returns the daily / monthly / annual cost of each mode and the annual savings of switching — quantifying the classic "driving is faster but pricier" vs "transit is cheaper but slower" trade-off.

Enter the number of treads, the rise and run, and the horizontal extensions at top and bottom; the tool computes the Pythagorean hypotenuse of the stair slope plus the level extensions to return the total handrail length — essential for DIY stair installs, ordering timber or stainless handrails.

Enter the final amount paid (tax + tip included), the tip percentage and the tax rate; the tool back-solves to recover the pre-tip subtotal, the tax amount and the actual tip — essential for reconciling receipts, checking credit-card slips and filing expense reports.

Enter pier diameter and total depth, plus an optional bell-bottom diameter and height; the tool sums cylinder + frustum volumes to return total concrete (cubic metres / cubic yards / 80-lb bag count) with a 10 % waste factor — essential for deck posts, fence piers, pergola feet and garage-pad DIY projects.

Enter roof footprint area, pitch (rise / run), bundles-per-square and waste factor; the tool returns slope factor, actual sloped roof area, roofing-square coverage (100 ft² each) and the bundle count rounded up after waste — essential for DIY re-roofing, contractor quotes and material orders.

Enter one-way distance, vehicle fuel consumption, fuel price, tolls and parking, plus the number of riders; the tool returns the total trip cost and each rider's share (driver included or excluded) — the standard fairness tool for office carpools, road-trips and shared rides.

Enter your total gift budget (holiday / wedding / birthday) and a recipient list with closeness weights (immediate family 3, friends 2, colleagues 1, etc.); the tool divides the budget proportionally to suggest a per-person amount — the rational-spending companion for Christmas, Lunar New Year and wedding-return-gift planning.

Enter your total wedding budget and guest count; the tool allocates the money across 12 standard categories (venue/catering, photo, attire, music, flowers, rings, etc.) using industry benchmark percentages and reports the per-guest average. Three presets — Classic, Reception-heavy (Asian banquet) and DIY — cover the most common styles.

Enter your dog or cat's weight; the tool applies the standard veterinary guideline (dogs 50–60 mL/kg, cats 60 mL/kg) to report daily water needs in mL and oz — essential for hydration, kidney health and hot-weather planning.

Enter total trip distance, tank capacity, fuel economy (L/100km or mpg), starting fuel and safety reserve %; the tool reports how many refuels you need and the distance between stops — essential planning for road trips and remote-area driving.

Enter your household bleach (sodium hypochlorite) concentration (e.g. 5.25 %) and dilution ratio; the tool returns the final NaOCl ppm concentration and compares it to CDC and WHO guidance for cleaning, surface disinfection and bodily-fluid spills.

Suggests distilled white vinegar (5 % acetic acid) and water mixing ratios by cleaning task (windows, floors, kitchen grease, limescale, coffee maker), outputs ml-by-ml recipes and warns about surfaces that vinegar should NOT touch (marble, hardwood, copper).

Choose a room type (living, kitchen, study, bathroom, bedroom, work desk, hallway…) and the room size (m² or ft²); the tool uses IESNA Lighting Handbook recommended illuminance (lux) to compute total lumen needs = lux × area, and suggests the number of fixtures based on a single-bulb output (typically 800–1600 lm) — useful for renovation, desk lamps, kitchen downlights and pendant-light planning.

Enter the guest count, party length and average drinks per guest per hour; the tool uses standard serves (wine 150 mL, sparkling 120 mL, spirits 30 mL) to compute how many 750 mL bottles to buy and splits them according to your red / white / sparkling / spirits ratio.

Enter your projector throw ratio (e.g. 1.2 standard, 0.5 short-throw, 0.25 ultra-short) plus the target screen diagonal (in / cm / m) and aspect ratio (16:9, 4:3, 2.35:1); the tool returns the lens-to-screen distance in mm / m / ft — useful for home theatre, meeting rooms and classroom installations.

Enter the guest count, meat type (steak, burger, chicken, pork, seafood, sausage) and whether it is the main protein; the tool applies Weber / Serious Eats per-guest portions (raw weight), accounts for 25–30 % cooking shrinkage and bone weight, and reports total raw meat to buy — useful for parties, family cook-outs and holiday BBQs.

Enter the recipe’s original servings and your target servings; the tool returns the scaling multiplier and converts common quantities (cups, Tbsp, tsp, lbs, grams, ml) to the new amounts — useful for scaling a recipe up for a party or down to a single portion.

Enter generator tank size, rated wattage, actual load % and fuel type (gasoline / diesel / propane / natural gas); the tool uses typical burn curves to estimate runtime in hours and fuel cost per kWh — useful for camping, home backup-power and job-site planning.

Enter the watts of an old incandescent bulb (or the lumens you want); the tool uses ENERGY STAR / EU energy-label reference tables to return the equivalent wattage in LED, CFL and halogen, plus annual electricity cost and savings — the question everyone Googles when buying replacement bulbs.

Measure the trunk circumference at breast height (DBH, 1.3 m above the ground), pick the species, and the tool applies the International Society of Arboriculture (ISA) species growth-factor method to estimate tree age — no need to fell the tree and count rings; works for urban park trees and backyard old trees.

Enter the power bank capacity (mAh), the phone battery capacity (mAh) and the conversion efficiency (typically 60–80 %); the tool converts mAh to usable Wh using the standard 3.7 V Li-ion voltage and returns how many phone charges you actually get — useful when shopping for a new power bank or planning a trip.

Enter your home size (sqft or m²), climate zone (mild / moderate / cold / very cold), wood type (hardwood / mixed / softwood) and stove efficiency; the tool uses the USDA Forest Service energy density (one cord ≈ 20 M BTU hardwood / 12 M BTU softwood) to estimate the cords of firewood you need for the heating season along with the equivalent stack volume in m³.

Enter the lawn area, grass species (Kentucky bluegrass, tall fescue, Bermuda, Zoysia and more) and seeding type (new vs over-seeding); the tool applies recommended lb-per-1,000-sqft rates from US Extension turfgrass guides to return the total seed weight in pounds, kilograms and g/m² — useful for backyards, schools, parks and golf-course seeding.

Enter the coffee dose (g) and target brew ratio (ristretto 1:1.5, normale 1:2, lungo 1:3); the tool returns the yield in grams plus a recommended extraction time window — useful for home espresso machines, semi-autos and portafilter dialing.

Enter the room or basement area and the dampness level (moderately damp through post-flood); the tool applies the ENERGY STAR / AHAM sizing table under the DOE 2019 standard (65 °F inlet) to return the required pints per day and L per day, plus a recommended retail model tier (20 / 30 / 50 pt).

Enter the number of people, trip days and meals cooked per day (breakfast, lunch, dinner + coffee/boiling); the tool applies backpacker and car-camping benchmarks (5–10 min boil time per person-meal) to return the isobutane or propane fuel needed in grams and standard canister count — so you neither over-pack nor run out.

Estimate fridge thawing (24 h per 2.27 kg) or cold-water thawing (30 min per 0.45 kg) time based on USDA safe-thawing guidance.

Enter your speed and the tool applies the 2-second (dry), 3-second (wet) or 4-second (night/heavy vehicle) rule to give the minimum following distance (in metres, feet and car-lengths).

A standard resistance-training volume metric: weight × reps × sets per exercise summed across the session gives total tonnage — handy for tracking week-over-week progression in a programme.

Cold brew comes in two styles: concentrate (1:4–1:8) you dilute later, and ready-to-drink (1:12–1:15). Enter how many cups you want and the strength preference and the tool returns the grams of coarse-grind coffee, the water volume, the dilution needed and the steep time — no more guessing.

Standard rule of thumb: drop oven temperature by 25 °F (~14 °C) and cut time by about 20 % for an air fryer. Enter the oven recipe's temperature and minutes and read the air-fryer equivalent — no more recipe-book guesswork.

Pizza value tracks area, not diameter. Enter the diameter and price of two pizzas and read price per cm² (or per in²) side-by-side to see which is genuinely cheaper.

TVs, set-top boxes, wireless chargers, always-on PCs and other appliances quietly draw a few watts every hour of the year. Enter the standby wattage and your electricity price to see how many dollars (and kWh) leak out per year.

Enter your streaming quality tier (SD / HD / 4K) and your monthly data cap to read how many hours of Netflix / YouTube / Disney+ you can watch before hitting the limit.

Enter an appliance's wattage (W), daily run-time and your electricity price per kWh, and read the daily / monthly / annual kWh and cost — with one-click presets for AC, space heater, fridge, TV, gaming PC and LED bulb. Universal: enter the tariff in any currency.

Enter tub capacity (litres or US gallons) and tap flow rate, and read how many minutes the bath will take to fill, total water used and a rough water-cost estimate — so you know when to come back and shut the tap off.

Enter sushi servings or cups of raw rice and read the matching grams of rice, water, rice vinegar, sugar and salt — using the classic Japanese 10 : 5 : 1 vinegar : sugar : salt ratio so first-timers can get sushi rice right on the first try.

Enter the number of pasta servings and the tool returns the classic Italian "1 L water : 10 g salt : 100 g pasta" gold standard — grams of pasta, litres of water, grams of salt and a suggested boil-water and cook time per pasta shape.

Enter your baking location's altitude (metres or feet); the tool returns standard high-altitude recipe adjustments — reduce sugar, reduce leavening, add flour, add liquid, raise the oven temperature, shorten the bake time — using the USDA / King Arthur Baking guidance.

Enter your TV or projector screen diagonal and aspect ratio (16:9, 21:9, etc.) and get the SMPTE (30°) and THX (36°) recommended viewing distances, plus the closest distance at which individual pixels become invisible for 1080p / 4K / 8K resolutions.

Enter the total finished volume or weight your project needs, plus the brand mix ratio (1:1, 2:1, 3:1, 4:1, 5:1, by volume or by weight); get the exact amount of Part A (resin) and Part B (hardener) to avoid a sticky cure from a wrong ratio.

Enter cake shape (6/8/9/10-in round, 9×13 rectangle, half-sheet, cupcakes), layer count, and finishing style (crumb-coat only / standard / heavy / piped) and get total buttercream needed in cups and grams — so you don't under-mix mid-decorate or throw away half a batch.

Enter the cups you want and strength preference (1:15 strong to 1:18 light); the tool returns ground coffee in grams, total brew water, bloom water and per-pour amounts — covers V60, Chemex and Kalita Wave pour-over methods.

Enter guest count, event duration and type (wedding toast / cocktail hour / dinner / NYE countdown); using the 750 mL ≈ 6 flutes-per-bottle standard, get bottles needed with ~10% buffer — no awkward run to the shop mid-toast.

Enter the thickness of the top board (the piece being fastened); using the carpentry 2×–3× rule, the tool returns the right nail or wood-screw length in mm, inches and US "penny" size, plus the minimum base-board thickness required.

Enter the roof footprint area, pitch and waste % allowance; using the North-American convention "3 bundles = 100 sq ft (1 square)", the tool returns total bundles and squares — what to order at Home Depot / Lowe's / B&Q.

Enter the Christmas tree height (feet) and density (basic / full / lavish); using the industry rule of "100 lights per foot of tree" the tool returns total string length and bulb count to buy.

Enter the LP / propane tank size (5 / 11 / 20 / 30 / 40 lb) and the appliance BTU/hr rating; the tool returns the continuous run-time in hours.

Enter your height (and optional inseam) and the tool returns the recommended frame size for road, mountain or hybrid bikes using standard fitting charts — so you arrive at the bike shop knowing the right ballpark.

Using the trail-food rule of 1.5–2.5 lb (680–1,130 g) per day at 100–130 kcal/oz, enter trip days, body size and intensity to plan total food weight and calorie budget.

Enter rolls on hand, sheets per roll, household size and daily use per person; the tool returns how many days the stockpile will last so you know when to restock.

Enter the board length, target piece length and saw kerf (typically 1.5–3.2 mm); using the formula "(total + kerf) ÷ (piece + kerf)", the tool returns the number of clean pieces and leftover waste — a woodworking DIY essential.

Enter the trunk-base diameter (inches/cm); using the National Christmas Tree Association rule of "1 quart per inch of trunk diameter per day", the tool returns daily water need, the larger first-day soak amount and minimum stand reservoir size.

Enter the number of films, average runtime, between-film break length and meal time; the tool returns total marathon duration — perfect for LOTR Extended, Star Wars Day or film-festival planners.

Enter baby age and changes per day; using Pampers / Huggies / AAP guidance per stage, the tool returns daily, weekly, monthly and yearly diaper usage plus the boxes you should stockpile.

Enter L × W × H (cm or inches); the tool returns the total volume in litres and compares it against major-airline (Cathay, AA, Ryanair, JetBlue, etc.) carry-on size limits, flagging if it exceeds.

Enter catchment-roof area, rainfall and runoff coefficient (metal / tile / asphalt); the tool returns harvestable water per event in litres / gallons — for rain-barrels, gardens and drought planning.

Enter flour, water, starter (with the starter's own hydration) and salt; the tool returns the dough's effective hydration % using baker's percentage — 75 % country loaf, 85 % ciabatta, 65 % bagel.

Enter turkey weight (lb / kg), stuffed or unstuffed, and oven temperature; using USDA / Butterball standards the tool returns refrigerator thaw time and total roasting time — Thanksgiving / Christmas essential.

Enter patio / walkway area and paver size (L × W) with a waste %; the tool returns total pavers to buy.

Enter total rise and target riser height (US 7"/175 mm international); using IRC / Blondel formulas the tool returns the number of risers and recommended tread depth.

Enter cooktop width and type (electric / gas / Chinese wok); using HVI 1900 and IRC guidelines, the tool returns the recommended minimum CFM.

Enter shower-head flow (GPM or L/min), shower length, hot-water share and inlet / outlet temperatures; returns per-shower and annual water use, kWh to heat the hot fraction, annual water + energy cost, and the savings from swapping to an EPA WaterSense 1.8 GPM low-flow head.

Enter tile area, tile size, tile thickness and joint width; using the industry grout-coverage formula (Mapei / Custom Building Products), the tool returns how many kg of grout to buy.

Enter slab length × width, rebar spacing (typically 12" or 300 mm) and edge clearance; returns the number of long-way and short-way bars plus total linear length so you can order materials.

Enter total rise and total run; using the Pythagorean theorem the tool returns stringer length, slope angle and recommended step count.

Enter tank capacity (L or US gal) and fuel economy (L/100km, MPG or km/L), pick a safety-reserve percentage; returns full-tank max range, practical range after reserve, and fill-ups needed for an optional trip distance.

Pick the rice type (white / brown / jasmine / basmati / sushi / arborio / glutinous / wild), amount (cup / g) and cook method (stovetop absorption or rice cooker); using Cook's Illustrated / Modernist Cuisine bench-tested ratios, returns the corresponding water amount and expected cooked yield.

Enter batch size (L / gal), current beer temperature, target CO₂ volumes and sugar type (corn / table / DME); using the Palmer "How to Brew" formula, returns priming sugar weight for bottle conditioning.

Enter height (cm / ft+in), weight (kg / lb) and riding style (all-mountain / freestyle / powder / free-ride); using Burton / Evo sizing charts, returns the recommended snowboard length range.

Enter pool volume (gal / L), pump flow rate (GPM / LPM) and daily turnovers (typically 1; 2 in heavy bather load); returns required pump runtime per day in hours.

Enter real-world shoot duration, target playback length and playback frame rate; returns total frames needed and interval (seconds) between shots.

Enter CPU and GPU TDP, drives, fans, RAM sticks and accessories; returns recommended PSU wattage with 80 Plus efficiency and headroom margin.

Enter system capacity, target coolant concentration (30 / 40 / 50 / 60 / 70 %), glycol type (EG / PG) and bottle strength (100 % pure / 50/50 pre-mix); returns concentrate and distilled water amounts to add, plus predicted freeze and boil points.

Enter room length × width (or total area), coverage per box and cutting waste % (5–10 % straight lay, 15 % diagonal); returns the boxes you need to order so you neither run short nor over-buy.

Enter original oven or stovetop cooking time; using Crock-Pot and Hamilton Beach manufacturer conversion charts, returns equivalent slow-cooker times on LOW and HIGH plus a suggested setting.

Enter number of pizzas, ball weight and target hydration / salt / yeast as baker's percentage (with optional oil and sugar); the tool instantly returns flour, water, salt and yeast in grams per Neapolitan / NY-style convention.

Enter guest count, party duration, the share of drinkers and your beer / wine / spirits mix to plan how many bottles and servings of each (plus soft drinks) to buy — with a 10 % safety buffer.

Enter the length, width and gravel-layer depth of a driveway or path to estimate the cubic metres / cubic yards of gravel needed and the approximate total tonnage.

Enter the number of bedrooms / living rooms / kitchens and average load per room to estimate total cubic feet and the recommended moving-truck size (10 / 15 / 20 / 26 ft).

Enter the wallpaper area (m² or ft²) and the paste manufacturer's coverage rate to find the total paste volume (litres) and the number of packets to buy.

Enter the hourly rate, total sitting hours, late-night surcharge and transport fee to estimate the total amount you owe the babysitter.

Enter the original sugar or honey amount in a recipe to get the substitute quantity, the matching liquid reduction and the recommended oven-temperature drop for successful baking.

Enter window width, drop, fullness ratio, hems and bolt width to compute total curtain fabric (m / yd) and how many fabric "widths" you need to cut.

Enter lawn area, sprinkler flow rate (L/min or GPM) and target watering depth (mm or inches) to compute how many minutes to run each session.

Enter vehicle efficiency (kWh / 100 km or kWh / 100 mi), electricity rate (per kWh) and charging loss to get the cost per 100 km / 100 mi, plus the cost per km and per mile.

Enter number of people, pasta type (long / short / egg / filled) and whether it is a main or side dish to get the total dry pasta in grams (with per-person g/oz, cooking water and salt).

Enter candle wax weight (g / oz), wax type (soy / coconut / beeswax / paraffin) and wick size to estimate total burn time and recommended per-session burn length.

Pick a tea type (green / black / oolong / white / pu-erh / Earl Grey / herbal), enter cup volume and strength preference to get suggested water temperature, leaves-per-cup and steep time.

Tick the appliances you want to keep running during an outage (fridge, AC, furnace, stove, lights, pumps, electronics…) — get the running and peak surge wattage and a recommended generator rated kW snapped to common sizes (3, 5, 7.5, 10, 12, 15 kW…).

Enter tank volume and adult fish size (inches / cm) to estimate how many fish you can keep using the classic "1 inch of adult fish per US gallon" rule, with conservative / standard / heavy bands.

Enter hours parked per day, hourly rate, daily cap and monthly pass price — get the cheapest option plus actual monthly and annual spend.

Enter hole diameter, depth, post diameter and number of posts — get concrete volume per hole (with 10 % waste) and bag count in 25 kg / 40 lb / 60 lb / 80 lb sacks.

Enter tank capacity (L or gal) and mist output rate (mL/h or gpd) to get continuous run hours, plus a reference for the output a room of your size needs.

Enter work seconds, rest seconds, rounds per set, number of sets and inter-set rest — instantly get the total Tabata / HIIT workout duration with per-set and per-round breakdowns.

Paste an article and the keyword (or phrase) to analyse — get total word count, occurrence count and percent density (including 2-grams), with the standard SEO 1–3 % sweet-spot recommendation.

Enter your height (with or without shoes) — using ANSI/HFES 100 and BIFMA G1 ergonomic formulas, instantly get the recommended seated desk height, standing desk height, monitor top edge height and eye-to-screen distance.

Enter your camera photo dimensions and the print size you want (4×6, 5×7, 8×10, A4, etc.) — instantly see which side gets cropped, what percent of the image is lost, and a visual preview of the surviving area.

Enter the weights of compost feedstocks (food scraps, coffee grounds, dry leaves, cardboard, etc.) and get the overall C:N ratio against the 25–30:1 sweet-spot recommended for fast hot composting.

List each ingredient with its weight and kcal per 100 g — the tool computes total kcal, total weight, kcal per 100 g and per-serving kcal so you can compare how energy-dense a recipe is.

Enter the total mass and water mass (or a wet- / dry-basis percentage) to instantly inter-convert wet-basis MC_wb = water/total and dry-basis MC_db = water/dry — essential for grain storage, woodworking and food drying.

Enter the coffee dose and target espresso yield to get the brew ratio (1:x), label the style (ristretto / normale / lungo) and back-solve dose or yield for any target ratio.

Enter water depth, bow height above water and expected conditions; the tool applies the seafarer rules of thumb (5:1 day, 7:1 overnight, 10:1 storm) to compute the rode length you need to pay out.

Convert between EC (mS/cm) and PPM on the 500-, 640- and 700-scales so you can compare readings between meters and growing guides.

Enter wet/leather-hard size plus drying (typically 4–8 %) and firing (typically 4–10 %) shrinkages to predict dried and fired sizes — or work backwards from a target final size. Earthenware, stoneware and porcelain presets included.

Compute the number and weight of briquettes for a BBQ from grill area, cook method (direct vs indirect) and duration — with refill timing.

Size gutters (5"/6"/7" K-style) and number of downspouts from roof drainage area and the local maximum rainfall intensity (mm/hr or in/hr) — based on SMACNA / IBC drainage standards.

Estimate working load limit (WLL) and minimum breaking strength (MBS) from rope diameter, material (nylon / polyester / Dyneema / manila) and a safety factor (typically 5:1) for rigging and climbing applications.

From plant daily water need, drip emitter flow rate (L/h), number of emitters and system efficiency — compute minutes per run plus daily, weekly and monthly water totals.

Enter height, weight and ability (beginner / intermediate / advanced) to get a recommended alpine-ski length (cm) per industry rules of thumb — beginner short, intermediate all-mountain, expert big-turn boards.

Recommend a surfboard volume in litres from rider weight, ability, fitness and board type — covering shortboard, funboard and longboard ranges.

Enter water temperature (°C / °F) to get the recommended wetsuit thickness (mm), style (spring / fullsuit / hooded) and whether you need booties, gloves or a hood — using the industry standard from O'Neill, Rip Curl and Patagonia.

Measure from the tip of your ring finger to the lower palm crease (mm or in) and get the matching adult tennis racket grip size (L0–L5, i.e. 4 + n/8 inch) using the ATP / USTA / ITF industry standard.

Recommend kayak paddle length in cm from paddler height and kayak beam width (recreational / touring / sea / whitewater) using the standard paddle-sizing reference chart.

Enter a horse's age to estimate its equivalent human age using the American Association of Equine Practitioners (AAEP) chart — sharp jumps in the first five years, then ~2.5 human years per horse year.

Convert a rabbit's age (from 1 month upward) to its human-year equivalent, life stage and per-month ageing rate using the House Rabbit Society / RSPCA chart.

Convert any recipe between instant (rapid-rise), active dry and fresh cake yeast using the standard 1 : 1.25 : 3 conversion ratio.

Pick a herb (basil, rosemary, thyme, oregano, mint, etc.) and a quantity to convert between fresh and dried using the 3 : 1 rule and herb-specific ratios.

Convert between carat weight and diameter (mm) for round brilliant-cut diamonds using the standard ideal-cut volume-density formula.

Enter frame rate (fps) and shutter angle to get per-frame exposure time (in seconds and 1/x form) plus a verdict on whether the look matches the 180° natural film rule, a crisper action look, a strobe-staccato action style, or a dreamy heavy-blur style.

Enter raw meat weight and cooking method (roast, grill, braise, fry) — or a custom shrinkage % — to estimate cooked yield; or work backward from a target cooked weight to find how much raw meat to buy. Essential for catering, meal-prep and meat-budget planning.

Convert *Minute of Angle* (1/60 of a degree, used on rifle scopes) to physical inches or cm at any distance: 1 MOA ≈ 1.047 in @ 100 yd. Enter angle and range to get group size or scope-click adjustment.

Enter your driving speed and reaction time (default 1.5 s) — get the "thinking distance" travelled before the brake is even applied. About one car length per second, 25 m at 60 km/h with a 1.5 s response.

Enter muzzle velocity and range — get bullet flight time and gravity drop drop = ½g(R/v)² in centimetres / inches, plus equivalent MOA and mil scope-click holdover. Vacuum ballistic model.

Enter venue area and expected attendance — get crowd density (people/m²) and the Fruin Level-of-Service grade (A–F) showing whether it is safe (crush risk starts above 4 people/m²).

Enter the length to decorate (tree height, eaves perimeter, railing) and the length of one light string — get the number of strings needed, total bulb count and total electrical load (W). Avoid over- or under-buying.

Pick a species (chicken, duck, goose, pigeon, quail, turkey, budgie, cockatiel, …) and a set date — get the expected hatch window, candling date, lockdown date and recommended incubator temperature / humidity.

Enter green-bean and roasted-bean weight — get the percentage weight loss, the implied roast level (light / medium / medium-dark / dark) and the green-bean mass you need to hit a target roasted batch. Essential for home roasters and small batch operations.

Choose wet brine (meat + water + salt) or dry cure (meat + salt only), enter the meat weight and target salt percentage — the tool returns the salt grams, the resulting brine concentration and a recommended cure time. Useful for roast meats, Thanksgiving turkey, bacon, charcuterie and pickle brines.

Enter a target running cadence (steps per minute, e.g. 180) — the tool returns the matching playlist BPM bands (one-beat-per-step = same BPM, two-steps-per-beat = half BPM), so you can pick tracks that lock to your footfalls.

Pick a drink (espresso, drip coffee, black tea, green tea, soda, energy drink, …) and a serving size to estimate total caffeine in mg and how it stacks against the 400 mg daily upper limit.

Enter the grams of 8 common oils (olive, coconut, palm, castor, shea, cocoa butter, sunflower, tallow); the tool uses each oil's SAP value to compute the exact NaOH (bar soap) or KOH (liquid soap), water and total batch weight, with adjustable 0–15 % superfat and 20–45 % water ratio.

Enter your planned depth (m / ft) — the tool returns the single-dive no-decompression limit (NDL) from BOTH the *PADI RDP 2014* (recreational standard) and the *US Navy 1959 Air Tables* (historical reference) and flags safety-stop, deep-range (> 30 m) and technical-diving (> 40 m) territory. For pre-dive awareness and student revision.

Enter the fermentation temperature (°C), target acidity and bottle-carbonation level — the tool returns estimated days for F1 primary and F2 secondary fermentation, using the classic Q₁₀ ≈ 2 temperature rule.

Enter fall distance, rope paid out, climber mass and rope softness — the tool returns the fall factor (0–2) and the peak impact force in kN at the climber, rope and top piece, using the classic Wexler / UIAA-101 Hookean-rope model.

Type an English word (up to 15 letters); the calculator sums the standard Scrabble letter scores, lets you mark double / triple letter / word premium tiles, and adds the 50-point "bingo" bonus when all 7 tiles are played.

Enter the container volume (mL), batch size, wax type (soy / coconut / beeswax / paraffin / palm / rapeseed / para-soy), fill ratio and fragrance-oil load — the tool uses the molten density of each wax to return wax grams and fragrance grams per jar and for the whole batch.

Enter lens focal length, sensor crop factor and IS / IBIS stops — the tool returns the slowest safe handheld shutter speed using both the classic 1 / (focal × crop) reciprocal rule and the stricter 1 / (2 f) variant for high-res sensors, snapped to the nearest camera click-stop.

Enter the tank capacity (cubic feet or litres — typical party tanks are 8.9 ft³ / 14.9 ft³ / 80 ft³) and the balloon diameter (9", 11", 16" latex), and the tool uses sphere volume math to report the realistic number of balloons fillable, the estimated lift per balloon, and a typical knot/loss allowance.

Pick species (dog / cat), enter body weight, activity level, life stage and the kcal per treat. The tool computes the WSAVA Resting Energy Requirement RER = 70·BW(kg)^0.75, scales it to Maintenance Energy MER by the activity / life-stage factor, then applies the standard veterinary "10 % treat rule" to return the maximum daily treat count and the kcal allowance — a quick way to prevent weight gain and nutrient imbalance.

Enter the roof catchment area (m² or ft²), the monthly / annual rainfall (mm or inches) and the runoff coefficient for the roof material (tile 0.9, metal 0.95, asphalt shingle 0.85, green roof 0.5). The tool returns the harvestable rainwater volume in litres, cubic metres, US gallons and imperial gallons — useful for sizing storage tanks, planning garden irrigation, sustainable houses, farms and school sustainability projects.

Enter the filament grams used, filament $/kg, print time, printer wattage (W) and electricity tariff. The tool returns material cost, electricity cost, energy (kWh), failure-adjusted cost and a suggested sale price including your chosen markup — useful for Etsy / eBay / Shapeways pricing, makerspace cost recovery and hobbyist budgeting.

Enter water depth, bow freeboard, expected tidal rise and the scope ratio for the rode type (all-chain 4:1, chain + rope 5:1, all-nylon rope 7:1, storm 10:1). The tool returns both the rode length to deploy and the swing radius the boat will trace — essential anchoring math for cruisers, anglers and weekend boaters.

Pick the pool shape (rectangular, round, oval, kidney / free-form) and enter the dimensions plus the shallow and deep-end depths. The tool uses the average-depth formula to return the total volume in litres, cubic metres and US gallons — used for refill planning, chemical (chlorine / pH) dosing and heating-energy budgets.

Enter dishwasher cycles per week, water (litres) per cycle, electricity (kWh) per cycle, water tariff and electricity tariff — the tool returns monthly and yearly water use, electricity use and total running cost. Useful for comparing old vs new units, eco vs normal modes, and dishwasher vs hand-washing.

Enter clip length and *render ratio* (minutes of render per minute of clip — varies hugely from an old laptop on 4K to a new GPU on 1080p). The tool returns the total render time, the estimated finish time and the electricity cost of the render (if you supply wattage and tariff). Useful for Premiere, DaVinci Resolve, Final Cut and Blender users planning overnight jobs.

Enter SHU (Scoville Heat Units) or capsaicinoid content (ppm) — the tool uses the standard *SHU ≈ 16 × ppm* conversion both ways and lists the typical SHU range of common peppers (bell, jalapeño, habanero, Carolina Reaper, pure capsaicin) for quick comparison.

Enter the wattage and time printed on the package (often 1100 W) plus the wattage of your home microwave; the tool applies new time = old time × old wattage ÷ new wattage to scale heating time — useful for ready meals, frozen vegetables, instant rice / oatmeal and cookbook recipes written for a different oven.

Enter the total tip pool for a shift and each worker's hours; the tool returns each person's pro-rata share. The fairness-by-hours pooling method used by restaurants, cafés and bars worldwide.

Paste a list of lap times (running track, pool, kart, motorbike), and the tool returns total time, mean lap, fastest and slowest lap, plus each lap's gap to the best. The training-analysis staple.

Enter charcoal type (lump or briquettes), starting weight and grill / vent configuration; the tool estimates high-, medium- and low-heat burn windows — useful for BBQ, smoking and outdoor cooking sessions.

Enter bike speed, tyre size (e.g. 700×25c) and front/rear chainring teeth — the tool returns pedal cadence (RPM). Useful for road cyclists, Zwift indoor training and gear-ratio selection.

Enter your inseam length; the tool returns the recommended saddle height (saddle top to bottom-bracket centre) using the LeMond rule inseam × 0.883 — the de-facto starting point for road cycling, Zwift indoor training and casual bike setup.

Enter chainstay length, largest chainring teeth and largest rear cog teeth; the tool returns chain length in inches / links using the Park Tool formula — essential when fitting a new chain, regearing or building a single-speed.

Enter your inseam length; the tool recommends a crank length using the LeMond rule (cm × 1.25 + 65 mm), mapped to a standard 2.5 mm step, and shows two common alternatives (× 0.20 short for TT, × 0.216 long / Zinn rule) — useful for bike fitting, TT bikes and track cycling.

Enter the weight (kg) of food inside the fridge or freezer and ambient temperature; the tool estimates total defrost time using a standard heat-transfer model — useful for fridge cleaning, power outages and moving day.

Enter wort volume, gravity, and for each hop addition the alpha-acid %, weight and boil time; the tool returns total bitterness IBUs via the Tinseth formula — the de-facto standard for homebrew beer recipes.

Enter the count of promoters (9–10), passives (7–8) and detractors (0–6). The tool returns NPS = % promoters − % detractors and benchmarks the result against industry tiers — the de-facto customer-experience metric.

Enter the building footprint area and the roof pitch (rise/run or angle) and the tool returns the actual roof surface area — for estimating shingles, asphalt rolls, metal panels or solar PV coverage.

Enter your monthly or annual gym fee and how many times you actually go each week; the tool returns the true cost per visit, annual outlay and the day-pass break-even — the quickest answer to "is this membership worth it?".

Enter weekly WFH days, daily commute cost, eat-out lunch cost and extra at-home electricity; the tool returns net annual savings and break-even days — the real-money value of hybrid or remote work.

Enter on-peak / mid-peak / off-peak kWh and the per-kWh price for each tier; the tool returns the monthly bill, blended average price and on-peak share — the right tool for sizing a TOU plan switch, home battery payback or load-shift schedule.

Enter points or miles needed, the equivalent cash fare and any taxes; the tool returns cents per point (the standard CPM metric) and benchmarks it against the 1–2 ¢ typical-fair band — the fastest answer to "should I pay cash or redeem points?".

Enter your age to get the socially cited acceptable dating age range (youngest to oldest) using the "half your age plus seven" rule.

Enter your dog's weight, the chocolate type and amount eaten to estimate the theobromine dose (mg/kg) and toxicity severity, and whether an emergency vet visit is warranted.

Estimate a dog's adult weight from its current age and weight using the growth-percentage method, with a small / medium / large / giant size class.

From an accrual rate per pay period and pay frequency, work out how much paid time off you build up over a year and by a given date.

From the clear railing length, baluster width and maximum gap, work out how many balusters you need and the even spacing — meeting the 4-inch (100 mm) safety-sphere rule.

From deck length and width, board width, gap and board length, estimate the number of decking boards, total linear metres and screws needed (with waste).

From keg size and pour size, work out how many servings a keg yields (allowing for foam loss) and the cost per glass.

From frame height, wire drop and the desired center-line height, calculate exactly where the hook should go on the wall.

From design stitch count, fabric count (stitches per inch) and margin, work out the finished fabric size you need to cut.

From pond length, width, maximum depth and edge overlap, calculate the length and width of liner you need to buy.

From ceiling height, ideal blade height off the floor and the fan's own height, work out the downrod length to use.

From wall length, height and block size, work out the retaining-wall blocks, cap blocks and base gravel you need.

From the room perimeter minus door openings, work out the total baseboard length and how many stock lengths to buy.

From the area to cover, the coverage per roll and a waste allowance, work out how many rolls of sod you need.

From a box's length, width and height, work out the sheet size, area and roll length of wrapping paper needed to wrap one gift.

Multiply a tint film's VLT by the glass's existing VLT to get the real combined visible light transmission.

Work out the carpet area for a room, add a waste allowance, and estimate the length needed for a given roll width.

Get a recommended rug size from your room dimensions and desired floor border, snapped to the nearest standard size.

From water volume and salinity percentage, work out how much salt and sugar a wet brine needs, in grams and teaspoons.

Compare two cars’ fuel economy to see the yearly fuel cost difference and how much you save over a given annual distance.

Work out food cost %, gross profit and a suggested menu price from ingredient cost and selling price.

From base time, increment and expected moves, estimate each player’s maximum clock time and the longest total game length — handy for scheduling tournament rounds.

Enter the number of players to get the minimum Swiss-system rounds needed to produce a clear winner (⌈log₂N⌉) and the games per round.

Split a total prize pool across placements by percentage, showing each place’s payout — for esports, poker, contests and betting pools.

From pool volume, current salinity and target ppm, work out how much salt to add (or water to drain) for a salt-chlorinator pool.

From grain temperature, target mash temperature and water-to-grain ratio, find the strike water temperature to heat your mash water to.

Work out the chocolate-to-cream ratio and amounts for ganache by chocolate type and use (truffles, filling, glaze).

Work out how much butter and flour to make a roux for a given amount of liquid and desired sauce thickness.

Work out how much gelatin (sheets or powder) is needed to set a given volume of liquid to a chosen firmness.

Find the candy stage (thread, soft-ball, hard-ball, hard-crack…) for a syrup temperature, adjusted for your altitude.

Work out how much cornstarch and cold water to thicken a sauce or gravy to a thin, medium or thick consistency.

From the volume of whipped cream you want, work back to the heavy cream, sugar and vanilla you need.

From a 1:N dilution ratio and the total mix you want, work out how much concentrate and how much water to use.

From the TV size, aspect ratio and your seated eye level, work out the recommended floor-to-centre, top and bottom heights for wall mounting.

Calculate the clean air delivery rate (CADR) an air purifier needs for a given room size and target air changes per hour.

Estimate coop floor area, outdoor run size, number of nesting boxes and roost length for a backyard flock by bird count and size.

Scale a batch of hummingbird nectar to the amount of sugar and water needed at a chosen strength (standard 1 part sugar : 4 parts water).

Work out the minimum current (amp) rating a solar charge controller needs from the total panel wattage and the battery bank voltage.

Estimate how many days a water softener runs between regenerations, and the capacity to buy, from household size, water hardness and resin grain capacity.

Estimate how long to dry-brine meat by weight and how much salt to use.

From meat weight and target percentages, work out the salt, Cure #1 pink curing salt and sugar for an equilibrium cure — and the resulting nitrite ppm.

From a sugar-to-water ratio (1:1 simple or 2:1 rich) and target amount, work out the sugar and water to use.

From the number of egg whites and meringue style (French / Swiss / Italian), work out the sugar and cream of tartar needed.

Look up the heat value (million BTU) per cord by wood species, then work out the usable heat (kWh, MJ) and fuel-oil equivalent from the number of cords and appliance efficiency.

Work out the millilitres of nicotine base, VG, PG and flavour needed for a target bottle size, nicotine strength, VG/PG ratio and flavour percentage.

Calculate the resin volume and weight needed to fill a mould, split into part A and part B by the mix ratio.

Work out how much fragrance oil (by weight) to add to your wax for a target fragrance load, scaled by the number of candles.

From a quilt’s length and width and your binding strip width, work out the total binding length, number of fabric strips and fabric needed.

Adjust boiling-water-bath canning processing time for altitude, since water boils cooler higher up and needs longer processing.

From water volume plus current and target salinity (ppt / specific gravity), work out how much marine salt to add.

Work out how many beads fit a bracelet or necklace of a given length from the bead diameter.

Estimate the total hay weight and number of bales needed to feed livestock from body weight, head count and days.

Calculate how many drops of essential oil to add to a carrier oil for a target dilution percentage.

Use Boyle’s law to estimate how many shots a compressed-air (HPA) paintball tank delivers from its volume, fill pressure and air used per shot.

From carton and pallet (or container) dimensions, work out cartons per layer, number of layers and the total that fit.

Compute shipment density from weight and dimensions, then estimate the US NMFC LTL freight class from the density band.

From how many generations each person is from their common ancestor, work out the exact cousin relationship — Nth cousin, M times removed.

From the starting ABV, target ABV and volume of spirit, work out how much water to add to reach bottling strength.

From your table dimensions and the drop you want, find the tablecloth size to buy for a rectangular or round table.

Work out the regulator pressure (PSI) to set for force-carbonating a keg from your beer temperature and target CO₂ volumes.

Estimate how much dry ice you need for a cooler based on the hours of cooling required and the sublimation rate.

Estimate the tent area and a suggested tent size from your guest count and event layout (cocktail, seated dinner, with dance floor or buffet).

Estimate the dance floor area and dimensions your guest count needs, using the rule that about 40% dance at once at roughly 4.5 sqft each.

From the binding length and strip width you need, work out the square of fabric required to make continuous bias tape and roughly how much fabric it uses.

Estimate how many balloons a balloon arch needs from its length, balloon size and how densely you pack them.

Work out your mash / brewhouse efficiency percentage from grain bill, malt potential, and the actual original gravity and volume you hit.

Wrap yarn around a ruler, count the wraps per inch (WPI), and match it to the standard yarn-weight category with suggested needle sizes.

From your feeding ratio (e.g. 1:5:5) and how much ripe starter you want, work out how much old starter to keep, how much flour and water to add, and how much to discard.

Convert a reel's rated line capacity to the length it holds when you switch to a line of a different diameter (e.g. braid vs mono).

Convert a spray nozzle’s known flow rate at one pressure to the flow at another pressure (flow scales with the square root of pressure).