Calculator
Cat calorie calculator
Find out exactly how many calories your cat needs each day — for maintenance or safe weight loss — using the same formula vets use.
Daily maintenance calories
≈ 130 g wet food + 34 g dry food per day
Assumes ~1.0 kcal/g wet and ~3.8 kcal/g dry. Use your food’s label in the food calculator.
✓ Formulas from veterinary nutrition guidelines · sources below · no sign-up, nothing stored · not a substitute for your vet
How this calculator works
We use the standard veterinary energy equations:
MER = RER × life-stage factor
| Life stage | Factor |
|---|---|
| Kitten (under 4 months) | × 3.0 |
| Kitten (4–12 months) | × 2.0 |
| Adult, neutered | × 1.2 |
| Adult, intact | × 1.4 |
| Adult, inactive / obesity-prone | × 1.0 |
| Senior (11+ years) | × 1.1 |
| Weight loss (applied to ideal weight) | × 0.8 |
Body condition is scored on the 9-point scale; each point above 5 is treated as roughly 10% above ideal weight. High activity adds 0.2 to the adult factor. These are starting points — every cat is an individual, so re-weigh every 2–4 weeks and adjust.
Sources: WSAVA Global Nutrition Guidelines; Merck Veterinary Manual — Nutritional Requirements of Small Animals.
Next: turn calories into portions with the cat food calculator, or check your cat against the weight chart.
Frequently asked
How many calories does a cat need per day?
A typical 4–5 kg neutered indoor adult needs roughly 200–250 kcal a day. The exact number depends on weight, body condition, age and activity — use the calculator above for your cat.
What is RER in cats?
Resting Energy Requirement: the calories needed for basic body functions at rest, calculated as 70 × (body weight in kg)^0.75.
How many calories should a cat eat to lose weight?
Veterinary guidance commonly starts at 0.8 × RER of the cat’s estimated ideal weight, targeting 1–2% body-weight loss per week. Always plan weight loss with your vet — rapid loss can cause hepatic lipidosis.
How many calories are in treats?
It varies widely (1–5 kcal per small treat). Keep all treats and human food under 10% of daily calories.