Free Tool
Cat Daily Calorie & Feeding Calculator
How much should you feed your cat? Enter your cat's weight, life stage, and the calorie number printed on your cat food, and this calculator estimates daily calories and the portion to serve — in cups or grams, split into meals. It uses the standard veterinary RER / MER energy formula, not the generous numbers on the back of the bag.
Feeding calculator
Estimated daily energy
0 kcal / day
Feed about
—
- Resting energy (RER)
- 0 kcal
- Activity multiplier
- 0× RER
- Based on
This is a general estimate, not medical advice
These numbers come from standard published veterinary energy formulas and are a starting point only. Your cat's real needs vary with metabolism, activity, and health. Always confirm portions with your veterinarian — especially for kittens, pregnant or nursing cats, and any cat with a medical condition. Weight loss should be gradual and vet-supervised; crash dieting can cause dangerous hepatic lipidosis in cats.
How the calculator works
Vets size a cat's food by calories, not by the scoop marks on the bag. Two published formulas do the work:
- Resting Energy Requirement (RER) — the calories a cat
burns at rest:
RER = 70 × (body weight in kg)0.75 - Maintenance Energy Requirement (MER) — RER multiplied by a life-stage / activity factor to reflect growth, neuter status, age, and weight goals.
The activity multipliers this tool applies:
| Situation | Multiplier |
|---|---|
| Kitten, 0–4 months (rapid growth) | 3.0 × RER |
| Kitten, 4–12 months | 2.0 × RER |
| Adult, intact | 1.4 × RER |
| Adult, spayed / neutered | 1.2 × RER |
| Senior (7+ years) | 1.1 × RER |
| Weight loss | RER at target weight, or 0.8 × RER |
| Weight gain (underweight) | 1.4 × RER (1.2 senior) |
Sources: The RER formula and these life-stage / activity factor ranges are the standard values published in the WSAVA Global Nutrition Guidelines and AAHA nutritional-assessment guidance, and are the same figures used on veterinary calorie charts. They are population averages — your individual cat may need up to ~20% more or less.