Free tool
Cat food calculator
Estimate how many calories your cat needs a day, and how much of your food that is, from its weight and life stage. A sensible starting point, with the one big warning cats come with: never crash-diet a cat.
How much a cat should eat
There is no single right amount, and the guide on the packaging is just that, a guide, usually pitched for an average, active cat. How much your cat should eat depends on its weight, whether it is neutered, its age, and how active it is, and the real proof is your cat's body shape over the following weeks. This calculator gives a sensible starting figure using the same method vets use, but treat it as a first estimate to adjust from rather than a fixed ration.
The method behind the number
The calculation works in two steps. First it estimates the calories your cat burns at rest, its resting energy requirement, from body weight. Then it multiplies that by a factor for life stage, because a growing kitten, a neutered indoor adult, and a cat on a vet-guided diet have very different needs. The result is a daily calorie figure, and if you tell it how many calories are in your food, it turns that into a daily amount for the bowl.
Watch the cat, not just the numbers
Whatever figure you land on, your cat is the real gauge. You should be able to feel its ribs easily under a light covering of fat, see a slight waist from above, and feel only a small tummy pad, not a swinging one. If the ribs are hard to find, it is time to talk to your vet about a gradual diet. If the cat feels bony and sharp, feed a little more. Adjust slowly, and reassess every couple of weeks.
Common questions
How many calories does my cat need a day?
Most lean, neutered adult cats need somewhere around 40 to 55 calories per kilogram of body weight a day, but the accurate way is to work out a resting need from weight and multiply by a factor for life stage. A neutered indoor adult needs less than a growing kitten or an intact, active cat of the same weight. This calculator does that maths, but your cat's body shape over the following weeks is the real check.
How much cat food should I put in the bowl?
Once you know the daily calories, divide by the calories in your food to get the daily amount. Wet and dry foods differ a lot in calorie density, so use the kcal figure on your specific food's packaging. If you feed both wet and dry, the two together need to add up to the daily total, which is where many cats quietly get overfed.
Why can't I just crash-diet an overweight cat?
Because rapid weight loss in cats can trigger a serious, sometimes fatal liver condition called hepatic lipidosis, or fatty liver. A cat that loses weight too fast, or stops eating, can become very ill. Overweight cats do need to slim down, but it must be gradual and vet-guided, not a sudden cut in food. This is the single most important difference from dieting a dog.
Should I feed my cat wet food, dry food, or both?
Either can be a complete diet, and many owners feed a mix. Wet food adds moisture, which suits cats well since they are not strong drinkers, while dry food is convenient and easy to measure. Whatever you choose, it is the total daily calories that govern weight, so if you feed both, count both toward the daily figure rather than treating one as extra.
This calculator gives a general estimate based on weight and life stage. Individual cats vary with breed, metabolism, and health, and some conditions change how much a cat should eat. Treat the result as a starting point, watch your cat's body condition, and speak to your vet about the right diet and amount, especially for kittens, seniors, and any cat that needs to lose or gain weight.