Updated
Cat food calculator
How much to feed a cat per day, worked the way a veterinary nutritionist does it: resting energy from body weight, a life-stage factor from the WSAVA tables (the feline table, not the dog one), then grams and cups from the bag’s own calorie figure. Both lines are shown so you can check the arithmetic.
261 kcal per day
neutered adult cat, 10 lb: RER 217.6 kcal × 1.2.
- Resting energy requirement, 70 × kg^0.75 (10 lb)
- 217.6 kcal
- Daily need: RER × 1.2 (neutered adult)
- 261.1 kcal
- Grams of food per day
- 65.3 g (a kitchen scale beats a cup: scooping over-feeds by up to 80 %)
- Cups per day
- 0.65 cups
- Meals
- Split the day into 2 or more measured meals; divide each figure above by the number of meals.
- Then
- A starting point, not a prescription: weigh and body-condition score in 2–4 weeks and adjust by about 10 %.
What this means
The factor is the whole answer, and it is what most feeding calculators hide or get wrong. A neutered adult cat needs RER × 1.2; a kitten or puppy up to × 2.5; weight loss ×0.8 on the ideal weight. The top-ranking cat calculator applies the dog table, which over-feeds a cat by about 30 %.
Grams are the honest unit. Dry foods range from about 3,000 to 4,500 kcal per kg and cups vary by kibble size, so a fixed "kcal per cup" assumption is a ±20 % error before the scoop error on top. This page never assumes a density: leave the bag fields blank and it shows kcal only.
Wet and dry together is common, and the safe way to mix them is by calories, not by volume: choose the wet share (70 % wet and 30 % dry is a popular split) and the page gives cans for the wet part and grams or cups for the dry part, so the total still equals the daily need. Cans are worked from the label’s own kcal per can; nothing is assumed.
Every figure here is a starting point. Metabolism varies by a third between individuals, which is why the WSAVA guidance puts "reassess in two to four weeks" first.
How many calories a cat needs a day
Daily calories by body weight: resting energy (70 × kg^0.75) times the WSAVA life-stage factor. Divide by your food's kcal per cup or per kg, printed on the bag, for the amount to feed.
| Body weight | Neutered adult (× 1.2) | Intact adult (× 1.4) | Weight loss (× 0.8) |
|---|---|---|---|
| 6 lb (2.7 kg) | 178 | 208 | 119 |
| 8 lb (3.6 kg) | 221 | 258 | 147 |
| 10 lb (4.5 kg) | 261 | 305 | 174 |
| 12 lb (5.4 kg) | 299 | 349 | 200 |
| 15 lb (6.8 kg) | 354 | 413 | 236 |
| 18 lb (8.2 kg) | 406 | 473 | 270 |
When to see a vet
- Weight changing faster than 0.5–1 % a week in either direction, on this or any plan.
- A cat that is eating the calculated amount and still losing weight, or is drinking noticeably more.
- A cat that stops eating for more than a day or two: cats on a crash diet risk hepatic lipidosis, a liver disease that can be fatal.
Formula and sources
Sources reviewed 18 September 2026. Each names the figure it supports.
- RER = 70 × kg^0.75 and the life-stage factors (MER = RER × factor) — WSAVA Global Nutrition Guidelines and Global Nutrition Toolkit, "Calorie needs for healthy adult dogs" and "… cats"
- Energy requirement equations behind the factors — National Research Council, Nutrient Requirements of Dogs and Cats, National Academies Press, 2006
- Weight loss fed to the ideal weight; treats within 10 %; recheck in 2–4 weeks — AAHA Nutrition and Weight Management Guidelines for Dogs and Cats, 2021
This page is an educational estimate, not veterinary advice.
Frequently asked questions
How much should I feed my cat per day?
Resting energy is 70 × (weight in kg)^0.75; multiply by the life-stage factor for the daily calories, then divide by the food’s kcal per kg for grams. A 10 lb neutered adult cat needs about 261 kcal a day.
Where do I find kcal per kg or per cup?
On the bag or tin, usually near the guaranteed analysis, as "metabolisable energy" or "ME". Most brands print both kcal per kg and kcal per cup or can. If only one is printed, enter that one; the other figure is simply not shown.
How do I feed a cat to lose weight?
Choose "weight loss" and enter the ideal weight rather than today’s: the diet is fed to the target at × 0.8, following WSAVA and AAHA guidance, and the safe rate is 0.5–1 % of body weight a week. The ideal-weight calculator gives the target from a body condition score.
Do treats count?
Yes. Enter the share of the day you give as treats (vets advise no more than 10 %) and the page takes it out before working out the food, so the bowl and the treats together stay at the daily need.
Why is my result different from another calculator?
Almost always the factor or the density. Tools that hide the factor may be using an intact-adult figure, or the wrong species’ table; tools that assume 350–400 kcal per cup are guessing the bag. This page prints both so the difference can be found.
How much wet and dry food should I feed my cat?
Split by calories, not by scoops. Enter the wet share (for example 70 %) and the kcal per can from the label: the page gives cans per day for the wet part and grams or cups for the dry part, and together they equal the daily need. A 10 lb neutered adult cat at 70 % wet on 85 kcal cans eats about 2.15 cans a day plus the dry balance.
How many cans of wet food a day for a cat?
Daily calories divided by the kcal per can. Set the wet share to 100 for an all-wet diet and enter the can’s kcal from the label; cans differ widely in size and energy, so the page never assumes one.
How many times a day should I feed my cat?
Most adult cats do well on two or more measured meals a day; kittens need three to four. Divide the daily grams, cups or cans by the number of meals.