How much should I feed my cat? Daily calories and cans, from weight and life stage
Vets size a cat's meals the same way for every species: RER = 70 x (weight in kg)^0.75, then multiply by a life-stage factor. A 10 lb (4.5 kg) neutered indoor cat has an RER of 218 kcal; times 1.2, that's 261 kcal a day, or about 2.7 cans of a typical 95-kcal 3-oz wet food. The same cat intact needs 305 kcal, a kitten 544. Fresh foods like Smalls or JustFoodForCats run roughly 28-40 kcal per oz, so 261 kcal is about 7.5 oz of fresh food a day. Then watch the ribs, not the bowl: feel for a waist from above and adjust 10% after two to three weeks.
Typical labels: 3-oz can about 70-100 kcal (95 is a good default), 5.5-oz can 130-200, dry food 300-450 per cup, fresh food 28-40 per ounce.
| Weight | kg | RER (kcal) | Neutered indoor (x1.2) | Intact adult (x1.4) | Kitten <12 mo (x2.5) |
|---|---|---|---|---|---|
| 5 lb | 2.3 | 129 | 155 | 181 | 323 |
| 8 lb | 3.6 | 184 | 221 | 258 | 460 |
| 10 lb | 4.5 | 218 | 261 | 305 | 544 |
| 12 lb | 5.4 | 249 | 299 | 349 | 624 |
| 15 lb | 6.8 | 295 | 354 | 413 | 737 |
| 20 lb | 9.1 | 366 | 439 | 512 | 915 |
RER = 70 x kg^0.75. Factors follow the conventions used in veterinary nutrition charts (Ohio State's veterinary medical center table, the Merck Veterinary Manual): neutered adult 1.2, intact adult 1.4, active/outdoor 1.6, weight gain 1.8, weight loss 1.0 at target weight, senior 1.1, kitten under 12 months 2.5. Cats vary by 10-20% around these numbers; the scale and the rib check are the final judges.
| Format | Typical kcal | 10-lb neutered cat needs | Notes |
|---|---|---|---|
| Wet food, 3-oz can | 70-100 kcal/can | 2.6-3.7 cans | High moisture, good for hydration and weight loss |
| Wet food, 5.5-oz can | 130-200 kcal/can | 1.3-2.0 cans | Cheaper per kcal than small cans |
| Dry kibble | 300-450 kcal/cup | 0.6-0.9 cups | Calorie-dense; measure with a scale, not a scoop |
| Fresh / refrigerated (Smalls, JustFoodForCats, Raised Right, Darwin's) | 28-40 kcal/oz (about 1.0-1.4 kcal/g) | 6.5-9.3 oz | Portioned packets; check the packet's kcal and divide |
| Freeze-dried / raw-style | Varies widely by brand | Per label | Rehydrate per instructions; kcal are listed rehydrated or dry, so read carefully |
Fresh cat food brands (Smalls, JustFoodForCats, Raised Right, Darwin's, Koha and similar) print kcal per packet or per oz on every package; densities cluster near 1.0-1.4 kcal/g. The brand's own feeding chart is calibrated to its food, so when the packet and this calculator disagree by more than 10%, trust the packet and re-check body condition in three weeks.
Cans-per-day charts on pet food bags are averages for average cats, and the average indoor cat is not average. The veterinary method starts from the resting energy requirement, the calories a cat burns at rest, then applies a factor for life stage and activity. It's the same RER engine our dog food calculator uses, with feline factors, because the underlying biology (Kleiber's law, the 0.75 exponent) is species-blind.
RER = 70 x (body weight in kg)^0.75. Convert pounds first: kg = lb x 0.4536. Daily calories = RER x factor. Portions per day = daily calories (minus any treat allowance) divided by your food's kcal per can, cup, or ounce.
Weigh your cat (hold the cat, step on the scale, subtract your weight) and enter that number. Pick the life stage: neutered indoor adult at 1.2 is most house cats. The kcal field is the one that matters: read it off your label, whether that's per 3-oz can, per cup of kibble, or per ounce of fresh food. Add a treat percentage if treats happen, and the calculator carves them out of the food portion automatically.
Take a 10 lb neutered indoor tabby eating a 95-kcal canned food. Weight in kg is 4.5. RER = 70 x 4.5^0.75 = 218 kcal. Times 1.2 for a neutered adult: 261 kcal a day, which is 2.7 cans, or about 0.9 cans per meal across three meals. Add a 10% treat budget (26 kcal, roughly one churu) and food drops to 235 kcal, or 2.5 cans.
Same cat on a fresh diet at 35 kcal/oz: 261 / 35 = 7.5 oz of fresh food a day, which is why fresh plans ship daily packets near that size. And a weight-loss case: a 15 lb cat whose target is 11 lb gets RER at the target, 70 x 5.0^0.75 = 234 kcal a day, not the 354 kcal that maintains a neutered 15 lb cat. Aim for about 0.5-1% of body weight lost per week and involve your vet, because fast dieting in cats risks hepatic lipidosis.
Feed the calculated amount for two to three weeks, then judge by feel: you want ribs under a thin fat layer, a visible waist from above, and no sagging belly pouch. Off target? Adjust the portion 10% and reassess. This is a starting point, not a prescription.
Vets compute resting energy then scale it: RER = 70 x (weight in kg)^0.75, times a life-stage factor. A 10 lb (4.5 kg) neutered indoor cat has an RER of 218 kcal, times 1.2 = 261 kcal a day. On a typical 95-kcal, 3-oz can of wet food that's 2.7 cans a day, split across meals. An intact cat at the same weight gets 305 kcal, and a kitten gets 544.
A 3-oz can runs roughly 70-100 kcal and a 5.5-oz can 130-200 kcal, but the exact number is printed on every label, usually as kcal ME/kg and kcal per can or per 100 g. Dry food runs about 300-450 kcal per cup. Use your label's number: assuming 95 when your can is 75 underfeeds by 20 percent, and the reverse oversizes meals the same way.
Fresh and raw-style cat foods (Smalls, JustFoodForCats, Raised Right, Darwin's, and similar) typically run about 28-40 kcal per ounce, roughly 1.0-1.4 kcal per gram. A 261-kcal cat needs 7-9 oz a day; at 35 kcal/oz it's 7.5 oz. Brands ship portioned packets with their own feeding charts, so check the packet's kcal figure and let the calculator convert it.
Use a factor of 1.0 and calculate at the target weight, not the current one. A 15 lb cat whose lean weight is 11 lb gets RER at 11 lb = 234 kcal a day, not the 354 kcal that maintains a neutered 15 lb cat. Weigh every two weeks and aim for about 0.5 to 1 percent of body weight lost per week. Cats that lose weight too fast risk hepatic lipidosis, so slow is genuinely safer here.
For most indoor cats, yes. A bowl that never empties plus a cat built to hunt 8-10 small meals a day is how half of house cats became overweight. Measured meals two to three times a day, or a puzzle feeder that slows eating, keeps the daily total honest. The exception is lean, self-regulating cats on multi-cat households where grazing is the practical option.
They should. The usual cap is 10 percent of daily calories: for a 261-kcal cat, that's 26 kcal, which is a handful of small treats or churu-style lickable paste. The calculator reserves a treat allowance and reduces the food portion so the daily total stays on target.