Cat Calorie Calculator
Daily calories for your cat, from a growing kitten to a weight-loss plan, with the grams per day for your food. The math runs in your browser and nothing is uploaded.
The formulas
- Resting energy requirement: RER = 70 x body weight in kg to the 0.75 power. The WSAVA feeding guide table for hospitalized dogs and cats uses the same formula.
- Kittens under 4 months: 3.0 x RER. Kittens from 4 to 12 months: 2.5 x RER. The factors come from Small Animal Clinical Nutrition, 5th edition, as tabulated in the Journal of Feline Medicine and Surgery.
- Neutered adults: 1.2 x RER. Intact adults: 1.4 x RER. These match the Pet Nutrition Alliance calorie calculator.
- Weight loss: 0.8 x RER on the ideal weight, the starting target reported in the Journal of Feline Medicine and Surgery.
- Grams per day: daily kcal divided by the food's kcal per kg, times 1000, rounded to whole grams.
How to use
- Enter your cat's body weight in kilograms. For a weight-loss plan, enter the ideal target weight instead of the current one.
- Pick the life stage: growing kitten, adult cat, or weight-loss plan. Kittens also need an age in months, and adults need a spayed or neutered answer.
- Optionally enter your food's energy in kcal per kg from the label, and the calculator adds a grams-per-day amount.
- Read the daily target, then weigh your cat every week or two and adjust the portion to keep a trim body condition.
Frequently asked questions
Is my cat's weight uploaded or stored anywhere?
No. The weight and life-stage inputs are used inside your browser tab and the math runs there. Nothing is sent to a server, nothing is saved on our side, and nothing is written to your browser's storage. The site sets no cookies and has no accounts; if an ad is shown, the ad network follows its own policies but never receives what you typed.
What formula does the calculator use?
Resting energy requirement, RER = 70 x body weight in kg to the 0.75 power. The calorie table in the WSAVA Feeding Guide for Hospitalized Dogs and Cats follows the same formula, and this calculator reproduces its rows: a 5 kg cat sits at 234 kcal and a 10 kg cat at 394 kcal.
Where do the life-stage factors come from?
Neutered adults get 1.2 times RER and intact adults 1.4 times RER, the values used by the Pet Nutrition Alliance calorie calculator, a collaboration of nine veterinary organizations. Growing kittens get 3.0 times RER before 4 months of age and 2.5 times RER from 4 to 12 months, the published growth factors in Small Animal Clinical Nutrition, 5th edition, as tabulated in the Journal of Feline Medicine and Surgery. Weight-loss plans get 0.8 times RER on the ideal weight, the starting target reported in the Journal of Feline Medicine and Surgery for feline weight management.
Is there a senior setting?
No, and that is deliberate. The sources this calculator follows give senior cats no separate published factor, so older cats are fed with the adult factors and the portion is adjusted to body condition. Senior cats are individuals, and changes in appetite or weight deserve a veterinary check rather than a formula.
Why does the kitten age matter?
Growth is not one flat number. Kittens younger than 4 months burn far more energy per kilogram than nearly grown ones, so the factor steps down from 3.0 to 2.5 times RER at the 4-month mark and stays there until about 12 months. Weigh kittens weekly and adjust portions to a steady, not maximal, growth rate.
Is this veterinary advice?
No. This calculator is a weight-management starting point based on published formulas, not a diagnosis or a feeding prescription. Individual cats vary, and energy needs can swing widely with health, activity, and environment. Set any weight-loss plan up with a veterinarian, and talk to one before large changes to your cat's diet.