Daily Caffeine Safe Limit Calculator

Enter height and weight to get your BMI and category (underweight / normal / overweight / obese).

Estimate daily BMR and TDEE using Mifflin-St Jeor or Harris-Benedict, with calorie targets for cutting and bulking.

Estimate body fat percentage using the US Navy circumference formula (neck, waist, plus hip for women).

Suggest ideal bedtimes or wake times based on 90-minute sleep cycles, so you wake up between cycles instead of mid-deep-sleep.

Estimate daily water intake from body weight, exercise duration and climate so you stay hydrated without overdoing it.

Compute pace per km / per mile from distance and time, or project finish time from a target pace — covers 5K, 10K, half- and full-marathon distances.

Compute 5 training heart rate zones from age and optional resting HR using the Karvonen formula (Z1 warm-up to Z5 max effort).

Estimate lean body mass (LBM), fat mass and body fat % from height, weight and sex using the Boer, Hume and James formulas.

Split a daily calorie target into grams of carbs, protein and fat at any macro ratio.

Estimate one-rep max from a sub-maximal lift (weight × reps) with Epley, Brzycki, Lombardi and Lander formulas, plus a 50–95% intensity training table.

Estimate body surface area from height and weight using the Mosteller, Du Bois, Haycock and Boyd formulas — commonly used in drug-dosing, chemotherapy and cardiac-index calculations.

Project a finish time at one distance from a known time at another distance using the classic Riegel formula T₂ = T₁ × (D₂/D₁)^1.06.

Compute mean arterial pressure from systolic and diastolic blood pressure with clinical bands and pulse-pressure context: MAP = DBP + (SBP − DBP)/3.

Compute cumulative smoking exposure in pack-years from cigarettes per day and years smoked, with lung-cancer-screening thresholds.

Divide waist by hip circumference and check the WHO risk bands — a quick screen for central obesity and cardiovascular risk.

Use METs, body weight and duration to estimate calories burned for common activities (running, hiking, swimming, cycling and more).

Pick the dose (mg) and the time you drank it; the calculator uses the standard ~5-hour caffeine half-life to project how many milligrams remain hour-by-hour, including the level at bedtime.

Bergman’s BAI estimates body-fat percentage from hip circumference and height alone (BAI = hip ÷ height^1.5 − 18) — no scale required.

Enter age, sex, height and weight to compare all five activity levels side-by-side — instantly see the daily calories you need to maintain weight.

Estimate blood alcohol concentration (BAC %) with the Widmark formula from drinks consumed, body weight, sex and hours elapsed — and compare against the Hong Kong 0.05% drink-driving limit.

Enter your distance covered in a 12-minute run to estimate VO₂ max and read off the age/sex fitness category.

Enter your bodyweight and training goal to get a science-backed daily protein range (g/day) and per-meal split, based on RDA, ISSN and ACSM/AND/DC guidelines.

Enter your last menstrual period (LMP) date and average cycle length to estimate the next ovulation day, fertile window and next period.

Estimate total body water (in litres) and the percentage of body weight using the Watson formula based on age, sex, height and weight.

Enter step count, height (auto-derives stride length) and body weight to estimate distance walked (km / mi), stride length, calories burned and your daily activity tier.

Enter a food's glycemic index (GI) and grams of carbs per serving to compute glycemic load GL = GI × carbs ÷ 100 — a better predictor of real blood-sugar response than GI alone.

Convert HbA1c (%) to estimated average glucose (eAG) in both mg/dL and mmol/L — and back again — to help diabetes and prediabetes patients read their lab reports.

Enter height, weight and body-fat percentage to compute Fat-Free Mass Index (FFMI) and the height-adjusted FFMI used to gauge muscularity.

Enter height and sex to compare the four classic ideal-body-weight formulas (Devine, Robinson, Miller, Hamwi), with their average and a ±10 % healthy-weight band.

Select 0–2 points for each of the five APGAR signs (Appearance / Pulse / Grimace / Activity / Respiration) to get the total APGAR score (0–10) and clinical band (normal / moderately depressed / severely depressed).

Pick eye-opening (1–4), verbal (1–5) and motor (1–6) responses to compute the Glasgow Coma Scale total (3–15) with mild / moderate / severe banding.

Enter systolic (SBP) and diastolic (DBP) blood pressure; the tool returns the pulse pressure and mean arterial pressure (MAP), then classifies the result as low / normal / elevated using the < 40, 40–60 and > 60 mmHg bands — the textbook signal for cardiovascular risk on a routine BP report.

Enter serum creatinine, age and sex; the tool applies the 2021 NKF / ASN-recommended CKD-EPI formula (race-free) to estimate glomerular filtration rate (eGFR) and classifies the result into CKD stages G1–G5 — the standard reading of a kidney-function lab report.

Enter age, weight, serum creatinine and sex; the tool applies the 1976 Cockcroft–Gault formula to estimate creatinine clearance (CrCl, mL/min) — still the FDA- and EMA-required formula for renal dose adjustment in most drug labels.

Enter waist circumference and height in any units; the tool returns the waist-to-height ratio (WHtR) and classifies it against the universal "keep your waist to less than half your height" cut-off (< 0.5) — a more sensitive central-obesity signal than BMI.

Computes the pediatric maintenance IV fluid rate (mL/hr and mL/day) from body weight using the Holliday-Segar 4-2-1 rule — the standard since the original 1957 publication.

Enter total cholesterol, HDL and triglycerides; the Friedewald equation (LDL = TC − HDL − TG / 5 or / 2.2 SI) estimates LDL-C and grades the result by NCEP ATP III risk bands.

Enter your current weight, target weight and daily calorie deficit; the tool uses the "≈ 3 500 kcal per lb of body fat" rule of thumb to project the number of weeks and the expected date you will reach your goal — a sanity check for setting a sustainable pace.

Enter pre / post-exercise body weight, fluids consumed and session length; the tool returns sweat rate per hour (L/h) and a suggested fluid intake every 15 minutes per the ACSM hydration guidelines — used by runners, cyclists, footballers and recruits.

Enter a drink's volume (ml) and alcohol content (ABV %); the tool converts to standard drinks using each region's definition (US 14 g, UK 8 g, AU/HK 10 g, JP 20 g of pure alcohol) and compares with WHO and national low-risk guidelines (e.g. ≤ 10 drinks/week).

Enter height and waist circumference; the tool applies the Thomas (2013) Body Roundness Index BRI = 364.2 − 365.5·√(1 − ((WC/2π) ⁄ (0.5·h))²). BRI tracks visceral fat and metabolic-disease risk more closely than BMI — a JAMA 2024 study linked BRI to cardiovascular mortality.

Enter visual acuity in Snellen (20/20, 20/40, etc.), metric Snellen (6/6, 6/12), LogMAR or decimal; the tool returns the other three formats with reference thresholds for driving licences and the legal-blindness cut-off — the standard conversion for ophthalmology, optometry and driving / occupational medicals.

Tick the burned regions (head, anterior / posterior torso, arms, legs, perineum) and the patient age group (adult / child); the tool applies Wallace's Rule of Nines to return total body-surface-area burned (%TBSA) and shows the Parkland fluid-resuscitation target — the standard field tool in emergency medicine, fire-rescue and first-aid.

Enter body weight, sex and the powerlifting total (squat + bench + deadlift, in kg or lb); the tool applies the Wilks 2020 coefficients to return the Wilks score — the standard way to compare powerlifters across body-weight classes and sexes, and the basis of best-lifter awards in IPF, USAPL and many federations.

Enter total carbohydrates, dietary fibre and sugar alcohols (per serving); the tool returns Net Carbs = total carbs − fibre − ½ × sugar alcohols. The standard keto / low-carb / diabetic-diet metric for absorbable carbs per serving.

Enter heart rate (HR) and stroke volume (SV); the tool computes cardiac output Q = HR × SV (L/min) and, given body surface area (BSA), the cardiac index CI = Q / BSA. Core hemodynamic math for emergency medicine, cardiology and nursing.

Enter weight and body-fat percentage; the tool returns BMR via the Katch-McArdle formula (BMR = 370 + 21.6 × lean body mass in kg) and TDEE after an activity multiplier. More accurate than Mifflin-St Jeor for lean and athletic body types where fat mass varies widely.

Enter the child's weight (kg), prescribed dose (mg ⁄ kg ⁄ dose or mg ⁄ kg ⁄ day), dosing frequency and adult-equivalent maximum; the tool returns the per-dose and total-daily amounts and flags when the adult cap is exceeded. The bread-and-butter weight-based dosing framework used in paediatrics worldwide.

Enter wet-bulb, globe and dry-bulb temperatures; the tool returns WBGT via the ISO 7243 formula 0.7·Tnwb + 0.2·Tg + 0.1·Tdb and classifies the result against the NIOSH / US military flag system (white / green / yellow / red / black) — the international standard for assessing heat-stroke risk in sport and occupational settings.

Enter cadence (steps per minute) and stride length (cm or m); the tool returns running speed (km/h, mph), pace (min/km, min/mi) and distance per minute — handy for runners on Garmin, Apple Watch and Strava tuning cadence vs stride.

Enter height and wrist circumference; the tool applies Grant's index r = height ÷ wrist circumference to classify body frame (small / medium / large) — used to adjust "ideal weight" estimates and reflects bone-structure differences that a single BMI value cannot.

Enter inseam (the floor-to-crotch length); the tool returns the recommended saddle height using LeMond's formula (inseam × 0.883, bottom-bracket to top-of-saddle) and the Hamley/Holmes method (~109% inseam to pedal), together with the 25°–35° knee-angle range for reference.

Enter treadmill speed (km/h or mph) and incline (%); the tool uses the ACSM running metabolic equation to return the equivalent flat-ground pace (min/km and min/mile) so you can compare indoor and outdoor effort.

Pick a fasting protocol (14/10, 16/8, 18/6, 20/4, OMAD, etc.) and your last-meal time; the tool returns when you can break the fast next, tomorrow's eating-window start and end, and total weekly fasting hours — useful for planning an IF schedule.

Enter your target hours per night plus the actual hours slept each of the past 7 nights; the tool returns total accumulated sleep debt (hours), average nightly shortfall, and how many consecutive "+1 h" nights are needed to clear it.

Enter your age; the tool reports the recommended sleep range from the US National Sleep Foundation's 2015 consensus guidelines (newborns 14–17 h, infants 12–15 h, preschoolers 10–13 h, adults 7–9 h, older adults 7–8 h) and a suggested bed-and-wake schedule.

Enter your height and a target BMI (e.g. 22.0); the tool computes the matching weight from W = BMI × (height/100)² in both kg and lb, plus how much you need to gain or lose from your current weight.

Enter the carbohydrate grams in a meal, pre- and post-meal glucose, the rapid-acting insulin units used and the glucose target; the tool applies the 500/TDD rule with the insulin sensitivity factor (ISF) to give a personalised ICR (g of carb per 1 U of insulin) and a suggested bolus.

Enter the total running time (hh:mm:ss) and distance (km or mile); the tool returns pace per kilometre, pace per mile, average speed (km/h, mph) and per-km / per-mile split tables — a quick way to compare training and race performance.

Enter your peak heart rate at end of exercise (HR_peak) and 1-minute post-exercise heart rate (HR_1min); the tool computes HRR = HR_peak − HR_1min — a cardiovascular fitness indicator from Cleveland Clinic (Cole et al., NEJM 1999): HRR ≤ 12 bpm is high-risk, 18–24 is average, ≥ 25 is good / athletic.

Enter your FTP (Functional Threshold Power, watts); the tool applies the Coggan 7-zone model to give the upper and lower bounds (Z1 Active Recovery → Z7 Neuromuscular Power) for every training zone — works for indoor trainers, road riding and Zwift sessions alike.

Enter your total daily insulin dose (TDD); the tool returns ISF — the mg/dL or mmol/L drop per 1 unit of rapid-acting insulin — via the 1800 / 1500 / 100 rule, a starting point for correction-bolus dosing in type-1 diabetes management.

Enter the control-event rate (CER) and the experimental-event rate (EER); the tool returns the absolute risk reduction ARR = CER − EER, the relative risk reduction RRR and the number needed to treat NNT = 1 / ARR — the cornerstone metrics for reading clinical trials and evidence-based medicine.

Enter events and non-events in the exposed and control arms (the classic 2×2 table); the tool returns the risk ratio (RR), odds ratio (OR), risk difference (RD) and their 95 % confidence intervals — the core statistics for cohort and case-control epidemiology.

Enter the patient weight in kg; the tool applies the Holliday-Segar 4-2-1 rule to compute the maintenance IV fluid rate (mL/hr) and total daily volume (mL/day) — the standard bedside estimate for paediatric and adult inpatient fluid orders, useful for clinicians, nurses and pharmacists.

Enter the measured QT interval (ms) and heart rate (bpm) (or RR interval); the tool reports QTc using all four standard corrections — Bazett, Fridericia, Framingham and Hodges — and flags values outside the normal range. Essential for ECG interpretation and monitoring of QT-prolonging drugs.

Enter total volume, infusion time and the tubing drop factor (gtt/mL; macro 10/15/20, micro 60); the tool returns the required drops per minute (gtts/min) and the equivalent mL/hr — the standard bedside calculation for nurses, ER and IV-therapy clinicians.

Enter serum Na⁺, Cl⁻ and HCO₃⁻ (optionally K⁺ and albumin); the tool reports the anion gap AG = Na − (Cl + HCO₃), the albumin-corrected gap and a classification of metabolic acidosis (high vs. normal gap) — a staple for emergency, ICU and nephrology interpretation of blood-gas and electrolyte panels.

Enter age and the tool applies the empirically-fit Tanaka et al. (2001) formula HRmax = 208 − 0.7 × age to estimate maximum heart rate (bpm), compares it with the traditional 220 − age rule and shows 50–90% intensity zones — the standard reference for running, cycling, HIIT and cardiac-rehab target heart rates.

Enter resting heart rate (RHR), maximum heart rate (HRmax) and a target intensity %; the tool applies the Karvonen formula THR = RHR + (HRmax − RHR) × intensity% and lists the 50 / 60 / 70 / 80 / 90 % training zones — more individualised than a flat percent-of-max because it accounts for the lifter's aerobic baseline.

Enter your height and the activity type (walking / jogging / running); the tool applies the standard regression coefficients (Pichler / NSCA) to estimate average stride length (cm per step) and converts it back to steps per km and steps per mile — useful for calibrating a pedometer, planning a walking workout or turning a step-count goal into real distance.

Enter age and sex; the tool returns the recommended daily Adequate Intake (AI) of dietary fiber in grams per the US Institute of Medicine (IOM 2005) reference tables — covering children, adults and older adults — plus the practical 14 g per 1000 kcal cross-check.

Enter daily energy intake and choose a guideline (WHO 5 % or 10 % of energy, AHA men 36 g / women 25 g); the tool reports the daily added-sugar ceiling in grams and teaspoons, plus its share of total calories — for sugar control, diabetes management and weight loss.

The tool shows daily sodium and salt limits per the major guidelines — WHO (adults < 2000 mg = < 5 g salt), US FDA (< 2300 mg), UK NHS (< 2400 mg = < 6 g salt) and the American Heart Association (ideal < 1500 mg) — adjusted by age and (optionally) hypertension / cardiovascular risk, and compares any single-food sodium amount against the daily budget.

Enter your total time in bed (lights off → out of bed), estimated fall-asleep latency and total awake time after onset; the tool returns sleep efficiency % and bands (< 75 % poor, 75–84 % fair, 85–89 % good, ≥ 90 % excellent), with the standard CBT-i sleep-restriction guidance keyed to those bands.

Enter HbA1c (%) or three-month average blood glucose (mg/dL or mmol/L); the tool applies the ADAG 2008 linear equation eAG (mg/dL) = 28.7 × A1C − 46.7 to convert in either direction — the standard cross-reference for self-monitored diabetes care, pre-visit estimation and lab-report interpretation.

Computes a daily fiber target using the U.S. National Academy of Medicine recommendation of 14 g per 1000 kcal (or a sex-/age-based table lookup) — a universal, simple guide for planning a high-fiber diet.

Enter an infant's weight (kg) and the number of feeds per day; the tool returns daily total formula volume and per-feed volume using international paediatric guidance (≈ 150 mL/kg/day, typical range 140–200 mL/kg/day) — a universal first-pass tool for parents of healthy term infants.

Look up the daily calcium target from the US NIH / IOM DRI tables (different for children, adults, pregnancy and seniors); enter age and sex / life stage and the tool reports the mg-per-day goal together with food equivalents (cups of milk, slices of cheese, servings of greens) — the standard reference for bone-health planning and child growth.

Enter age, sex, life stage (pregnancy / lactation / menstruating) and diet type (omnivore / vegetarian); the tool reports the daily iron target in mg using the NIH RDA tables — vegetarians multiplied by 1.8 to reflect lower bioavailability — the reference tool for anemia prevention, women of reproductive age and pregnant users.

Enter age, sex and life stage (pregnancy / lactation); the tool returns the daily magnesium mg target using the NIH RDA tables (adult men 400–420 mg, women 310–320 mg) and converts it into common food portions — an essential mineral for nerves, muscles, heart rhythm and bones.

Enter age, sex, life stage and your preferred unit (IU or mcg); the tool returns the daily vitamin D target from the NIH / IOM Dietary Reference Intakes — infants 400 IU AI, ages 1–70 600 IU and > 70 years 800 IU. It also shows the adult Tolerable Upper Intake Level (UL = 4 000 IU / day) and equivalent food servings (salmon, cod-liver oil, fortified milk, egg yolks, UV-exposed mushrooms).

Enter age, sex and life stage; the tool returns the daily potassium mg target from the US NASEM 2019 DRI / NIH ODS Potassium Fact Sheet AI table (adult men 3 400 mg, women 2 600 mg, pregnancy 2 900 mg, lactation 2 800 mg) and converts it into common high-potassium food servings (banana, baked potato, avocado, spinach, white beans).

Enter age, sex, life stage and smoking status; the tool returns the daily vitamin C mg target from the NIH / IOM Vitamin C Fact Sheet RDA (adult men 90 mg, women 75 mg, smokers +35 mg) and converts it into common food portions.

Enter age, sex and life stage; the tool returns the daily zinc mg target from the NIH / IOM Zinc Fact Sheet RDA (adult men 11 mg, women 8 mg, pregnancy 11 mg, lactation 12 mg) — central to immunity, wound healing and the sense of taste / smell.

Enter age, sex and life stage; the tool returns the daily selenium µg target from the NIH ODS Selenium Fact Sheet RDA (adults 55 µg, pregnancy 60 µg, lactation 70 µg, UL 400 µg) — a trace mineral essential to antioxidant defence, thyroid-hormone synthesis and immunity.

Enter age, sex and life stage; the tool returns the daily folate target in µg DFE from the NIH ODS Folate Fact Sheet RDA (adults 400, pregnancy 600, lactation 500, supplement UL 1000 µg / day) — the B-vitamin central to cell division, red-blood-cell formation and the prevention of fetal neural-tube defects.

Enter your training goal (maximal strength, hypertrophy, muscular endurance, power) and load intensity (% 1RM); the tool returns evidence-based rest-interval seconds between sets and the matching set / rep ranges, per NSCA Essentials of Strength Training (4th ed.) and ACSM guidelines.

Look up your daily vitamin B12 RDA (μg/day) by age, sex and pregnancy / lactation status using NIH ODS values, with B12 amounts in common foods and supplementation notes for vegetarians and vegans.

Look up your daily iodine RDA (μg/day) by age, sex and pregnancy / lactation status using NIH ODS values, with iodine content in iodised salt, seafood and common foods — guarding against deficiency (goitre) and excess (thyroid dysfunction).

Look up your daily vitamin A RDA (μg RAE/day) and tolerable upper intake (UL) by age, sex and pregnancy / lactation status using NIH ODS values; converts retinol and β-carotene to RAE so you can avoid deficiency (night blindness) and retinol overdose.

Paste a list of RR intervals (in ms, comma- / space- / newline-separated); the tool returns RMSSD = √(mean((RR_{i+1} − RR_i)²)), SDNN, mean heart rate, and an interpretation following the 1996 Task Force HRV standards — handy for sanity-checking HRV figures from a Garmin, Apple Watch or Polar device.

Enter the shoe type (max-cushion, daily trainer, racing flat and more), runner weight tier and miles already logged; the tool uses the 300–500 mile sports-medicine wear-out range to return the miles remaining and a months-of-use estimate at your current cadence — handy for avoiding knee pain and plantar fasciitis from worn midsoles.

Caffeine's half-life averages about 5 hours — a 200 mg morning coffee still leaves ~100 mg in your blood at 5 pm and ~50 mg by 11 pm. Enter the dose and time taken to see exactly how much is still circulating when you try to sleep.

BMI Prime = BMI ÷ 25 — expresses any BMI as a fraction of the normal-weight upper limit, so 1.00 means right at the cap and 1.20 means 20 % above it. Enter height and weight to read it instantly.

Spherical equivalent SE = Sphere + (Cylinder ÷ 2) collapses a cylindrical (astigmatism) prescription into a single spherical power — routinely used for ordering contact lenses, refractive-surgery screening, and basic vision reports. Also returns the vertex-compensated corneal-plane power for high Rx.

Enter pre-pregnancy height and weight (for BMI), gestational week and current weight; the tool returns the recommended total weight-gain range and weekly rate for singleton or twins based on the Institute of Medicine (IOM/NAM 2009) guidelines, comparing to actual gain.

Enter current age and sex; using the WHO Global Health Observatory period life table, the tool estimates remaining life expectancy and projected age at death assuming present-day mortality.

Using the dermatology 2 mg/cm² standard, work out how many grams of sunscreen (≈ the "shot-glass rule") you need for full body or each zone, then estimate reapplication interval from the classic "SPF × natural burn time" formula.

Enter trail distance, elevation gain and walking pace; using outdoor educator Paul Petzoldt's "energy miles" rule (+2 miles per 1,000 ft gain), the tool returns effective distance, estimated time and a difficulty rating.

Enter race distance, projected finish time and carb intake target (g/h); based on the 30–90 g/h sports nutrition range, returns how many gels and at what spacing.

Enter your 12-minute run distance (m or mi), age and sex; the tool estimates VO₂max via Cooper's 1968 JAMA formula and maps it to a six-band age/sex fitness classification.

Enter age (and optional resting HR); compare HRmax estimates from Fox (220−age), Tanaka, Gellish and the Nes / HUNT3 formula side-by-side, plus Karvonen training-zone bpm ranges.

Enter DEXA-scan T-score (and optional Z-score); classifies as normal / osteopenia / osteoporosis per WHO 1994 + ISCD 2019 criteria and shows relative fracture-risk multiplier.

Enter your best 20-minute average power (watts) to get your FTP (= 20-min × 0.95) and the seven Coggan training zones (Z1 Recovery through Z7 Neuromuscular).

Enter the total water volume (ml) — get the grams of salt, glucose (or substitute sucrose) and optional potassium chloride needed for a WHO/UNICEF low-osmolarity ORS, the standard rehydration recipe for diarrhoea worldwide.

Enter your age and habitual reading distance — get a quick estimate of the near-add power (+0.50 to +3.00 D) for off-the-shelf reading glasses, based on the Hofstetter 1944 accommodation formula and standard optometric guidance.

Compute your MAF maximum aerobic heart rate (zone-2 ceiling) using Dr. Phil Maffetone's 180-formula: 180 minus age ± a correction based on health and training status.

Enter current and target hair (or beard) length and the calculator returns how many months — at the population-average growth rate of ≈ 1.25 cm/month for scalp hair and ≈ 1 cm/month for beards — it will take to reach the goal. Useful for post-chemo regrowth, post-shave timeline, gender-transition grow-out and post-surgical hair recovery planning.

Enter both parents' heights and the child's sex; the Tanner mid-parental formula estimates the child's adult height with a ±8.5 cm 95 % confidence interval.

Enter body weight and population (healthy adult, pregnant, adolescent, child) — using EFSA / FDA / ACOG mg/kg ceilings the tool returns today's daily ceiling and the single-dose ceiling, and converts both into equivalent cups / cans of drip coffee, espresso, black & green tea, cola and energy drink.

Enter the finished volume you want to mix — using the WHO low-osmolarity ORS recipe the tool returns grams of table salt, sugar plus optional KCl and trisodium citrate, with no-scale teaspoon equivalents.

Enter your height (cm or inches) and skill level (beginner, intermediate, speed) — the tool returns recommended rope length handle-to-handle. Formula: height × 1.5 (beginner) or height + 30 cm (speed-rope).

Enter systolic and diastolic blood pressure (mmHg); the tool returns the AHA / ACC 2017 category — Normal, Elevated, Hypertension Stage 1, Hypertension Stage 2 or Hypertensive Crisis — used by clinicians worldwide for adult screening.

Enter age, sex and life stage; the tool returns the *Adequate Intake* (AI) for vitamin K (K1 phylloquinone + K2 menaquinone) in µg / day per the US Institute of Medicine DRI tables and converts the target into the grams (or tablespoons) of kale, spinach, natto, broccoli or olive oil you would need to hit it.

Pick an electrolyte ion (Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl⁻ and more); enter milliequivalents (mEq) or milligrams (mg); the tool uses mg = mEq × (atomic mass ÷ valence) to convert both directions — matching IV-drip prescriptions, oral supplements, drug labels and electrolyte amounts on food labels.

Enter height, sex and mode (walking, jogging, sprinting); the tool uses the Williams coefficients to return stride length (cm and inches), steps per kilometre and steps per mile — useful for calibrating pedometers, smart watches (Apple Watch, Garmin, Fitbit) and treadmills, and for converting a daily 10 000-step target into real distance.

Enter body weight and the daily split between standing and sitting; the tool uses MET coefficients (sitting 1.3, standing 1.8) to estimate the extra calories burned per day — handy for weight-loss tracking and ergonomics decisions.

Enter your daily protein target (g) and meal count (2–6 meals/day); the tool divides the total evenly and compares each meal to the leucine-trigger threshold (25–40 g per meal) — a standard reference for muscle gain, fat-loss muscle retention and post-bariatric nutrition.

Enter fasting plasma glucose and fasting insulin. The tool returns HOMA-IR = (FPG × FPI) / 22.5 (SI units) — the standard 1985 Matthews insulin-resistance index — and compares against typical cutoffs (< 1 sensitive / 1–2 average / ≥ 2.5 resistant).

Enter the first day of the last menstrual period (LMP) and today's date. The tool uses Naegele's rule to return gestational age in weeks + days, estimated due date (EDD) and trimester — the global obstetric / midwifery standard.

Enter treadmill speed (km/h or mph) and grade (%). The tool uses the Jones & Doust (1996) + ACSM running-metabolism formula to return the equivalent flat outdoor speed and pace — used to compare treadmill and outdoor training loads.

Enter a recent race result (distance + finish time). The tool applies Jack Daniels's VDOT model to predict equivalent finishing times at other distances (5K, 10K, half, full marathon) and lists matching training pace zones.

Enter fasting triglycerides (TG) and fasting plasma glucose (FPG); the tool returns the TyG index = ln(TG × FPG / 2) — a surrogate for insulin resistance that needs no insulin assay. Widely used in cardiometabolic risk screening and often more reproducible than HOMA-IR.

Enter the 2 × 2 contingency table of two raters scoring the same items (two categories × two raters). The tool returns the observed agreement p_o, expected-by-chance agreement p_e and Cohen's κ = (p_o − p_e) / (1 − p_e), classified using the Landis–Koch scale (slight / fair / moderate / substantial / almost perfect) — a workhorse for medical-diagnosis reproducibility, machine-learning labelling and psychometric studies.

Tick the seven Wells criteria (DVT signs, PE most likely diagnosis, HR > 100, recent surgery/immobilisation, prior DVT/PE, haemoptysis, active cancer); the tool computes the Wells score (0–12.5) and stratifies pulmonary-embolism probability into low / moderate / high (or the dichotomised PE-unlikely / PE-likely groupings) per Wells 1998/2000 — used for emergency-department triage.

Enter age and tick the six CHA₂DS₂-VASc comorbidities (CHF, hypertension, diabetes, prior stroke/TIA/thromboembolism, vascular disease, female sex); the tool returns the 0–9 total, the annualised ischaemic-stroke risk (% / year) and the ESC 2020 oral-anticoagulation recommendation.

Tick the four Centor items (tonsillar exudate, anterior cervical adenopathy, fever > 38 °C, absence of cough) and enter age for the McIsaac adjustment; the tool returns the 0–5 total and corresponding group-A streptococcal (GAS) infection probability band (≈1 %, ~10 %, ~17 %, ~35 %, ~50 %) to guide rapid-antigen testing or empirical antibiotics.

Enter the five ABCD² items (age ≥ 60, BP ≥ 140/90, clinical features: unilateral weakness +2/speech disturbance +1, duration ≥ 60 min +2/10–59 min +1, diabetes); the tool returns the 0–7 total and the 2-day, 7-day and 90-day post-TIA stroke risk (%).

Enter haemoglobin, blood urea, systolic BP, heart rate, sex, and comorbidities (melaena, syncope, liver disease, cardiac failure); the tool returns the 0–23 Glasgow-Blatchford Score (GBS) — the standard ED triage tool for upper-GI bleeding. GBS = 0 identifies very-low-risk patients who can be considered for outpatient follow-up.

Enter arterial oxygen partial pressure PaO₂ (mmHg or kPa) and inspired oxygen fraction FiO₂ (0.21–1.0); the tool returns the P/F ratio and the 2012 Berlin ARDS severity band (mild ≤ 300, moderate ≤ 200, severe ≤ 100).

Enter the 5 CURB-65 items (confusion, urea > 7 mmol/L, RR ≥ 30, SBP < 90 or DBP ≤ 60, age ≥ 65); the tool returns the 0–5 score, the matching 30-day mortality band and the corresponding outpatient / inpatient / ICU disposition guidance.

Enter history suspicion, ECG findings, age, cardiovascular risk factors and troponin level; the tool returns the 0–10 HEART score and the matching 6-week MACE (major adverse cardiac events) probability — the standard chest-pain triage rule in the emergency department.

Tick the three bedside criteria (altered mental status GCS < 15, RR ≥ 22 /min, SBP ≤ 100 mmHg); the tool returns the 0–3 qSOFA score. A score ≥ 2 flags suspected sepsis and higher mortality risk per the Sepsis-3 consensus (JAMA 2016).

Tick the eight clinical factors (CHF, hypertension, age ≥ 75 / 65–74, diabetes, stroke / TIA, vascular disease, female sex); the tool returns the 0–9 CHA₂DS₂-VASc score and the matching annual stroke risk — the standard tool for guiding anticoagulation in atrial fibrillation.

Enter respiratory rate, SpO₂ (with Scale 2 for hypercapnic respiratory failure), supplemental-oxygen status, systolic BP, pulse, consciousness (ACVPU) and temperature; the tool returns the 0–20 NEWS2 score — the UK Royal College of Physicians 2017 standard adopted across the NHS for early detection of clinical deterioration in adults.

Enter heart rate and systolic blood pressure; the tool returns the classic Shock Index (SI = HR ÷ SBP), the Modified Shock Index (HR ÷ MAP), and the Age-adjusted SI (Age × SI) — bedside emergency indicators of occult shock, haemorrhage, and early sepsis.

Enter age, AST, ALT and platelet count; the tool returns FIB-4 = (Age × AST) ÷ (Platelets × √ALT) — Sterling et al. 2006 non-invasive liver-fibrosis index, widely used to stratify advanced fibrosis risk in chronic HCV, NAFLD and MASLD.

Enter total cholesterol (TC) and HDL cholesterol ("good" cholesterol); the tool returns the TC / HDL ratio with *Framingham Risk Score* risk bands — a more reliable cardiovascular predictor than total cholesterol alone (target < 3.5; > 5 in men, > 4.4 in women is high risk).

Enter age, sex, total cholesterol, HDL, systolic BP (with treatment status), smoking and diabetes; the tool applies the *Framingham 2008 General Cardiovascular Disease* equation (D'Agostino et al., Circulation 2008) to return the 10-year CVD event probability and cardiovascular age — the long-standing risk model behind ATP III, JBS3 and AHA guidance.

Enter a rowing distance and time; the tool converts to your /500m split, average speed and Concept2 power watts = 2.80 ⁄ pace³ — the standard indoor-rowing training metrics.

Pick both parents' ABO blood group and Rh factor; the tool lists every blood type a child could inherit under Mendelian genetics.

Enter height and weight to compute the Ponderal Index (PI) = mass ÷ height³, a body-size measure that stays more consistent than BMI for very tall, very short or newborn bodies.

Enter serum total calcium and albumin to correct measured calcium for a low albumin, estimating the true calcium status.

Enter measured sodium and glucose to estimate the true sodium level before hyperglycemia dilutes it.

Enter sodium, glucose and urea (BUN) to calculate serum osmolality; supply a measured value to also get the osmolar gap used to screen for toxic alcohol poisoning.

Enter body weight and burn area (%TBSA) to get the 24-hour IV fluid volume from the Parkland formula, split into the first 8 hours and the next 16 hours.

Enter serum iron and total iron-binding capacity (TIBC) to compute transferrin saturation (TSAT = iron ÷ TIBC × 100%) for iron-status assessment.

Enter urine and plasma sodium and creatinine to compute the fractional excretion of sodium (FeNa%), used to distinguish prerenal from intrinsic acute kidney injury.

Compute ideal body weight (Devine formula) and adjusted body weight from height, actual weight and sex — commonly used for drug dosing in obese patients.

Estimate total blood volume from sex, height and weight using Nadler's equations, plus blood volume per kilogram.

Compute A Body Shape Index (ABSI) from waist circumference, height and weight (BMI) to gauge health risk linked to central obesity.

Compute the absolute neutrophil count (ANC) from the total white cell count and the neutrophil percentage (segmented + bands) to grade the severity of neutropenia.

Use Winter's formula to estimate the expected PaCO₂ from serum bicarbonate (HCO₃⁻) in metabolic acidosis, checking whether respiratory compensation is appropriate.

Score cervical dilation, effacement, station, consistency and position to get the Bishop score, gauging cervical ripeness and the likelihood of a successful labour induction.

Work out a premature baby's corrected (adjusted) age from the birth date and gestational age at birth, for fairer developmental milestone tracking.

Work out how many days a prescription will last (days' supply) from the total quantity dispensed and the daily dose.

From patient weight and a per-kilogram dose, compute the single and daily drug dose and convert it to millilitres of liquid medicine.

Convert International Units (IU) to and from milligrams (mg) / micrograms (mcg) for vitamins A, D, E and C using standard conversion factors.

Enter grams of protein, carbs, fat and alcohol to get total calories and the macro percentage breakdown using Atwater factors.

Enter bodyweight, sex and total lifted to get your DOTS score — a fair way to compare strength across different bodyweights.

Work out the daily creatine loading and maintenance dose (and per-serving amount) from body weight.

Estimate VO₂max from your 1-mile walk time, ending heart rate, body weight, age and sex.

Compute your SWOLF score from strokes and seconds per pool length to gauge swimming efficiency (lower is better).

Compute the MELD and MELD-Na score from bilirubin, INR, creatinine and sodium to gauge end-stage liver-disease severity and transplant priority.

Compute the Child-Pugh score from bilirubin, albumin, INR, ascites and encephalopathy to grade cirrhosis severity as class A, B or C.

Assess venous thromboembolism (VTE) risk in hospitalised medical patients with the Padua Prediction Score to guide thromboprophylaxis.

Score acute stroke severity with the 15-item NIH Stroke Scale, giving a 0–42 total and a severity band.

Estimate major bleeding risk for atrial-fibrillation patients on anticoagulation with the 0–9 HAS-BLED score.

Assess the clinical probability of deep vein thrombosis (DVT) with the Wells prediction score, stratified into low, moderate and high risk.

Grade acute pancreatitis severity and mortality risk with the Ranson criteria (at admission and 48 hours).

Work out your critical swim speed (CSS) threshold pace and training zones from a 400 m and 200 m time trial.

Score anxiety over the past two weeks with the 7-item GAD-7 scale, giving a 0–21 total and a severity band.

Score depression over the past two weeks with the 9-item PHQ-9 questionnaire, giving a 0–27 total and a severity band.

Assess obstructive sleep apnea (OSA) risk with the 8-item STOP-BANG questionnaire, giving a 0–8 score and risk band.

Rate your chance of dozing in 8 everyday situations to get a 0–24 Epworth daytime-sleepiness score and band.

Screen for hazardous drinking with the 3-item AUDIT-C questionnaire, giving a 0–12 score with sex-specific cut-offs.

Estimate blood alcohol concentration (BAC) from drinks, body weight, sex and time using the Widmark formula.

Calculate smoking pack-years from cigarettes per day and years smoked to gauge lung-cancer screening risk.

Estimate the calories burned and distance walked from your step count, weight and height.

Compute the Mentzer Index from mean corpuscular volume (MCV) and red-blood-cell count (RBC) to help distinguish iron-deficiency anemia from thalassemia trait.

From reticulocyte percentage, hematocrit and a maturation correction, compute the reticulocyte production index to judge whether the bone marrow is responding adequately to anemia.

Convert your running pace to an equivalent flat-ground pace for a given uphill or downhill grade, using the Minetti cost-of-running model.

Compute the Maddrey Discriminant Function (mDF) from prothrombin time and serum bilirubin to gauge severe alcoholic hepatitis prognosis.

Score the BODE index from BMI, airflow obstruction, dyspnoea and exercise capacity to estimate COPD survival prognosis.

Use the Caprini score to grade a surgical patient’s venous thromboembolism (VTE) risk and suggested prophylaxis.

Use one known race result to predict your finish time and pace at another distance (5K, 10K, half, marathon).

Divide power in watts by body weight to get W/kg and compare it against a rider-category reference table.

Estimate how long unprotected skin can stay in the sun before burning, based on the UV index and your skin type.

Normalise Olympic weightlifting totals across bodyweights using the official Sinclair coefficient to get a comparable Sinclair Total.

From body weight and loading intensity (g/kg), work out the daily carbohydrate grams and calories to load before an endurance event.

Compute the alveolar–arterial oxygen gradient from FiO₂, PaO₂ and PaCO₂, with an age-expected upper limit.

Plan a negative split from a goal finish time — first-half and second-half times plus per-km or per-mile pace.

Compute how long a medical oxygen cylinder will last from its gauge pressure, safe residual, cylinder size and flow rate.

Use Bart Yasso's 800m repeats rule to predict your full-marathon finish time and pace from your average 800m interval time.

Estimate the calories in a drink from its serving size, alcohol content (ABV) and residual carbohydrates.

Compute the IPF GL points that let lifters be compared across bodyweight and sex, from bodyweight, sex, event type and total lifted.