Cat calorie calculator
How much a cat should eat is easy to get wrong, and the cost of guessing is a slow slide into too heavy or, in an old cat, too thin. This calculator uses the same resting-energy formula vets use to estimate her daily calories. Enter her weight and what you are aiming for, and it gives a sensible starting number, one to check against your vet’s, not to replace it.
How much does she weigh, and what are you aiming for?
For weight loss, feed to her target weight, not her current one, and only with your vet.
Estimated calories to keep a healthy weight
262calories (kcal) a day
Her resting need (RER) is about 218 kcal a day; the number above applies a 1.2× factor for this goal. To turn calories into portions, check the kcal per cup or canon her food’s label and divide.
This is an estimate, not a prescription. Every cat is different, and your vet should set the real number, especially for weight loss, which must be slow and supervised.
How many calories does a cat need?
The estimate rests on a formula every vet uses. A cat’s resting energy requirement (RER), the calories she burns just existing, is 70 times her body weight in kilograms to the power of 0.75. Her real daily need is that RER multiplied by a life-stage factor: the Association for Pet Obesity Prevention puts a typical neutered adult cat at about 1.2 to 1.4 times RER, an indoor or low-activity cat a little lower, and a weight-loss plan at roughly 0.8 to 1.0 times RER. This tool uses one sensible value for each goal, which is why its number is a starting point rather than a precise ration.
Cat calorie chart by weight
The same formula, worked out for the weights most cats fall into. The maintain column uses the calculator’s 1.2 factor for a typical neutered indoor cat; slim down uses 0.8 and is read against the weight she should be, not the weight she is; gain uses 1.4. These are kilocalories, which is what a food label means by “calories.”
| Weight | Resting need (RER) | Maintain (1.2×) | Slim down (0.8×) | Gain (1.4×) |
|---|---|---|---|---|
| 6 lb (2.7 kg) | 148 kcal | 178 kcal | 118 kcal | 207 kcal |
| 7 lb (3.2 kg) | 167 kcal | 200 kcal | 134 kcal | 234 kcal |
| 8 lb (3.6 kg) | 184 kcal | 221 kcal | 147 kcal | 258 kcal |
| 9 lb (4.1 kg) | 201 kcal | 241 kcal | 161 kcal | 281 kcal |
| 10 lb (4.5 kg) | 218 kcal | 262 kcal | 174 kcal | 305 kcal |
| 11 lb (5.0 kg) | 234 kcal | 281 kcal | 187 kcal | 328 kcal |
| 12 lb (5.4 kg) | 249 kcal | 299 kcal | 199 kcal | 349 kcal |
| 13 lb (5.9 kg) | 265 kcal | 318 kcal | 212 kcal | 371 kcal |
| 14 lb (6.4 kg) | 280 kcal | 336 kcal | 224 kcal | 392 kcal |
| 15 lb (6.8 kg) | 295 kcal | 354 kcal | 236 kcal | 413 kcal |
| 16 lb (7.3 kg) | 310 kcal | 372 kcal | 248 kcal | 434 kcal |
| 18 lb (8.2 kg) | 338 kcal | 406 kcal | 270 kcal | 473 kcal |
| 20 lb (9.1 kg) | 366 kcal | 439 kcal | 293 kcal | 512 kcal |
Two cautions on reading it. A cat who is already thin from illness or age belongs with her vet’s number, not the gain column, since the reason she is thin matters more than the arithmetic; the guide to a senior cat losing weightcovers that. And the slim-down column is not “what a 14-pound cat should eat,” it is what a cat whose healthy weight is 14 pounds eats while she gets there.
Turning calories into how much to feed
Calories only help once they become a portion. Every cat food lists its energy as calories (kcal) per cup or per can, usually in the small print, so divide her daily target by that figure to get her daily amount. Then measure it, ideally by weight: an eyeballed scoop is easily off by a third, enough to undo a whole plan. There is more on this in the guide to feeding a senior cat, and if she is switching foods, on wet versus dry.
If she needs to lose weight, go slow
The one goal to be careful with is weight loss. Trim the calories too hard and a cat can lose muscle and, worse, develop a dangerous liver condition. VCA is firm that you should never put an obese cat on a diet without veterinary supervision, because too-rapid weight loss can cause hepatic lipidosis. A safe plan aims for only 1% to 2% of body weight per week, calculated for her target weight and overseen by your vet. The fuller method is in the guide to helping a senior cat lose weight safely.
To use this page as a cat weight loss calculator, enter the weight your vet wants her to reach rather than the weight she is now, choose “slim down,” and take that figure as the ceiling to check against your vet’s plan. A 14-pound cat whose healthy weight is 11 pounds is fed for 11, which the chart above puts at about 187 calories a day, and then weighed every week or two to make sure the loss stays inside the 1% to 2% band. If it is faster than that, or she stops eating, the plan needs the vet again, not a smaller portion.
Why this is an estimate, not a prescription
Two cats of the same weight can need noticeably different amounts, because activity, health, and metabolism all move the number. An older cat with a fast thyroid burns through calories, while a sedentary, neutered cat needs fewer than the average. Use this figure as a sanity check on whether you are roughly over- or under-feeding, take it to her check-up, and let your vet set the target she actually eats to.
Common questions
How many calories should a cat eat a day?
It depends on her weight and goal, but the standard estimate starts from her resting energy requirement (RER), which is 70 times her body weight in kilograms to the power of 0.75. A typical neutered ten-pound cat needs roughly 260 calories a day to maintain her weight, but your vet's number for your cat is the one to trust.
How do I turn calories into how much food to give?
Check the calories per cup or per can on your cat's food label, then divide her daily calorie target by that number to get her daily portion. Weighing food on a kitchen gram scale is far more accurate than a measuring cup, and small differences add up over a day.
How many calories does a cat need to lose weight?
Fewer, and only under veterinary guidance. Weight loss is usually planned at around 0.8 times RER calculated for her target weight, not her current one. Because rapid weight loss in cats can cause fatal liver disease, your vet sets the calories and the pace, which should be slow.
Is a cat kcal calculator the same as a calorie calculator?
Yes. The calories printed on cat food are kilocalories (kcal), the same unit this calculator and chart use, so a food listing 95 kcal per can against a target of 260 kcal a day works out to a little under three cans. A cat kcal calculator is a calorie calculator using the label's own unit.
Is this cat calorie calculator accurate?
It gives a reasonable estimate using the same RER formula vets use, but it is a starting point, not a prescription. Real needs vary with activity, health, and individual metabolism, so use the number as a sanity check and let your vet set your cat's actual target.
Biscuit’s trouble runs the other way: at sixteen, with her kidneys asking a lot of her, keeping weight on her is the job, so I watch this number to make sure her little meals add up to enough. Whichever way your cat leans, the point of a figure like this is not to ration her to the calorie. It is to catch, early, the quiet drift toward too much or too little, while it is still easy to fix.
Sources
- Association for Pet Obesity Prevention, Veterinary DER & MER Calculator (RER formula and factors)
- VCA Animal Hospitals, Creating a Weight Reduction Plan for Cats
This calculator is for general guidance and does not replace veterinary advice. Your vet should set your cat’s calorie target, especially for weight loss or any medical condition.