Cat Daily Calorie Needs Calculator
How many calories should my cat eat per day? This free cat daily calorie needs calculator answers that with the same RER/DER formulas veterinarians use: enter your cat's weight, pick a life stage and activity level, and get daily calorie needs plus how many cups of food that means. Results update instantly as you type, and everything runs in your browser — no sign-up, no downloads.
Enter your cat's numbers
Fill in all three values below. The estimate updates as you type.
Your results
Enter your cat's weight, life stage, and food calories to see the estimate.
How to use this calculator
Weigh your cat in pounds (a kitchen scale works for small cats; for larger cats, weigh yourself holding the cat and subtract your own weight). Pick the life stage or activity level that fits best, and enter the calories per cup printed on your cat food's label — this is usually listed as "kcal/cup" on the bag. The daily calorie target and cups per day appear instantly.
Choosing weight loss or weight gain adjusts the daily target with the standard veterinary factor. Because changing a cat's diet carries risks — especially weight loss in overweight cats, which can trigger liver problems — talk to your vet before switching to one of these modes.
Split the daily cups into two or three meals rather than free-feeding if you want predictable weight control. You can also press Calculate to recompute on demand.
How it works
This calculator uses the standard veterinary two-step method:
- RER (resting energy requirement) — the calories a resting cat burns: RER = 70 × (weight in kg)0.75. Converting pounds to kilograms (divide by 2.20462), a 10 lb cat weighs 4.54 kg, so RER ≈ 70 × 4.540.75 ≈ 218 kcal/day.
- DER (daily energy requirement) — RER multiplied by a life-stage factor: DER = RER × factor. An indoor neutered cat uses ×1.2, so 218 × 1.2 ≈ 261 kcal/day.
Finally, the calculator converts calories into food volume: cups per day = DER ÷ kcal per cup. At 350 kcal per cup, that is 261 ÷ 350 ≈ 0.75 cups per day.
This is a guidance estimate, not veterinary advice. The RER/DER formulas describe average cats; metabolism, body condition, and health can shift real needs. Check with your veterinarian before changing how much you feed your cat.
Frequently asked questions
How many calories should my cat eat per day?
Most indoor neutered adult cats need roughly 200 to 300 kcal per day, depending on body weight. The calculator above uses the veterinary RER/DER formula: a 10 lb indoor neutered cat needs about 261 kcal per day, while an active outdoor cat of the same weight needs about 348 kcal per day. Kittens need more per pound than adults.
What is the RER formula for cats?
RER (resting energy requirement) equals 70 times body weight in kilograms raised to the power of 0.75: RER = 70 × kg^0.75. Daily energy requirement (DER) is then RER multiplied by a life-stage factor, such as 1.2 for an indoor neutered cat or 2.0 for a growing kitten.
How do I convert my cat's daily calories to cups of food?
Divide the daily calorie target by your food's calories per cup, which is printed on the bag or can label. For example, 261 kcal per day divided by 350 kcal per cup gives about 0.75 cups per day. The calculator above does this conversion for you automatically.
Can I use this instead of my vet's feeding advice?
No. This calculator gives a guidance estimate based on standard veterinary formulas, not medical advice. Always check with your veterinarian, especially for kittens, seniors, cats with health conditions, or when putting a cat on a weight-loss or weight-gain plan.