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Pet Food Daily Portion Calculator (Dog / Cat)

Enter your pet's species (dog or cat), body weight, life stage (puppy / kitten / adult / senior / gestation / lactation) and activity level; the tool applies the NRC 2006 ("Nutrient Requirements of Dogs and Cats", National Academies Press) and WSAVA Global Nutrition Committee two-step method: (1) compute Resting Energy Requirement RER = 70 × BW(kg)^0.75 via the standard allometric scaling; (2) apply the life-stage × activity factor to get Maintenance Energy Requirement MER = factor × RER; (3) convert MER to grams of dry food using the food's energy density (kcal / 100 g, the "ME" line on the bag). RER, MER and the factor are all displayed alongside the gram total for easy cross-check with your vet's recommendation. Runs entirely client-side.

Daily food portion

g/day

Maintenance Energy Requirement (MER)

kcal/day

Resting Energy Requirement (RER)

RER = 70 × BW(kg)^0.75 (NRC 2006); MER = life-stage × activity × RER. Grams = MER ÷ food energy density. These are starting estimates — adjust ±10% every 1–2 weeks based on body-condition score. For special conditions (diabetes, CKD, pancreatitis) consult your veterinarian.

Formula

RER = 70 × BW(kg)^0.75 ; MER = factor × RER ; grams/day = MER ÷ (food kcal/100g) × 100

Frequently asked

My dog is overweight — can I just feed this calculated amount to lose weight?

Use the *target* weight (the BCS 4–5/9 ideal weight your vet can estimate), not the current weight, to back out the calorie target. The tool returns the MER needed to maintain that target. For active weight loss, multiply by 0.8 (a 20% reduction) and aim for 1–2% body weight loss per week. Re-weigh every 2 weeks and switch to maintenance once BCS hits 5. Don't drop calories abruptly — transition over 7–10 days and keep protein and fibre intake high.

How much do puppies and kittens eat compared with adults?

Growth-phase energy is 2–3× adult maintenance per kg body weight. NRC factors: puppy 0–4 mo = 3.0, 4–12 mo = 2.0; kitten 0–4 mo = 2.5, 4–12 mo = 2.0. Reason: rapid musculoskeletal growth plus high activity. Split into 4 meals/day under 4 months, 3 meals at 4–6 months, 2 from 6 months on. Use a growth-specific or "all life stages" food — not weight-loss or senior formulas. The tool applies the right factor automatically; before 8–10 weeks, follow your vet's or breeder's weaning plan because that transition has special protein and feeding-frequency rules.

How do I handle wet food or raw diets?

Same approach — what matters is the food's kcal/100g, not its form. Typical canned wet food is 70–110 kcal/100g (it's mostly water); frozen raw is 130–180 kcal/100g. Enter the chosen food's ME in the energy-density field and the tool converts to grams. For mixed feeding split the daily MER — e.g. 60% from dry / 40% from wet. Tip: wet food's high water content benefits kidney health (especially for cats), but the daily gram total runs 3–5× larger than dry — don't be alarmed by the volume.

The result differs from the bag's feeding chart — which one is right?

Bag charts typically run 5–20% *high* (safety margin to avoid "not enough" complaints). This tool uses NRC formulas and maintenance factors, which are closer to the individual animal's actual need. If your pet is already overweight (BCS ≥ 6/9), following the bag will keep them overweight. Use the tool's MER as your starting point and adjust ±10% every 1–2 weeks based on weight and BCS. Note: highly active dogs (working / sporting dogs running 1+ hour/day) or very lean dogs (BCS < 4) may genuinely need more than the tool indicates.

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