Pet Food Portion Calculator
Daily and per-meal food quantity for a dog or cat, from its weight and activity level.
Results
What this tool does
The resting energy requirement uses the standard veterinary relationship of 70 times body weight to the power 0.75, which accounts for small animals burning proportionally more than large ones. Energy density varies a lot between foods — take the kcal per kilogram from the bag rather than the default, because it changes the answer more than anything else here.
Formula
RER = 70 × (weight in kg)^0.75 ; daily requirement = RER × factor
Variables
| Symbol | Meaning | Unit |
|---|---|---|
w | Animal's weight | kg |
fa | Activity factor | — |
kd | Food energy density | kcal/kg |
nm | Meals per day | — |
GD | Food per day | g/dia |
GM | Food per meal | g |
RE | Calories | kcal |
ME | Calories | kcal/dia |
BG | Mass | kg/a |
Worked example
- Animal's weight20 kg
- Activity factor1.6
- Food energy density3600 kcal/kg
- Meals per day2
- Food per day294.2 g/dia
- Food per meal147.1 g
- Calories662.0 kcal
- Calories1059.2 kcal/dia
- Mass107.4 kg/a
Limitations
- This tool is informational only. It does not diagnose, treat or replace a qualified health professional. Speak to a doctor before making decisions about your health.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- Coverage and consumption figures vary between products. Take the values from the manufacturer's datasheet for the product you are actually using.
Frequently asked questions
What activity factor should I use?
Commonly quoted veterinary factors run from about 1.0 for a strictly weight-loss diet, through 1.2 to 1.4 for a neutered indoor adult, 1.6 for a typical active adult, and 2.0 or more for a working dog or a growing puppy. They are population averages: the real check is body condition over a few weeks, and a vet should set the factor for any animal that is overweight, underweight or unwell.