petculate

No. 07Feline energy reference

Cat Calorie Calculator

Most indoor cats need somewhere between 170 and 300 kcal a day, which is less than almost everyone pours. This tool runs the vet math for yours: RER = 70 × (weight in kg)0.75, times a feline life-stage factor. Add the calories from your food's label and it converts the target into cans or cups.

For weight loss, enter the target weight, not current.
On the label. A 3 oz can: ~70–90 kcal. Dry food: ~350–450 kcal/cup.

How feline calories are calculated

Cats use the same base formula as dogs, the Resting Energy Requirement: RER = 70 × (kg)^0.75. The daily target multiplies RER by a feline life-stage factor from the WSAVA and AAHA nutrition guidance:

Feline life-stage factors (× RER)
Life stageFactor
Kitten (growth)2.0–2.5 (we use 2.5)
Adult, spayed/neutered1.2
Adult, intact1.4
Senior / less active1.1
Weight loss0.8 × RER at ideal weight

The factors are smaller than a dog's because most indoor cats move less than almost any dog. That's also why the number surprises people. A 10 lb cat's whole day fits in one generous scoop of dry food.

Daily calorie needs by weight (neutered adult)

Estimated kcal/day at 1.2 × RER
WeightCalories per day
6 lb ≈ 178 kcal
8 lb ≈ 221 kcal
10 lb ≈ 261 kcal
12 lb ≈ 299 kcal
14 lb ≈ 336 kcal
16 lb ≈ 371 kcal
20 lb ≈ 439 kcal

Obesity is the most common feline nutrition problem vets see, and it develops one extra quarter-cup at a time. Weigh monthly. If the trend is up, trim the portion about 10% and recheck. And if a chubby cat suddenly stops eating, call your vet the same week; rapid fasting is dangerous for cats.

Frequently asked questions

How many calories does a cat need per day?

A typical spayed or neutered indoor cat needs about 1.2 × RER, where RER = 70 × (weight in kg)^0.75. That comes to roughly 200 kcal/day for an 8 lb cat and 260 kcal for a 10 lb cat. Intact cats run higher, seniors a bit lower, and kittens need more than double per pound.

How much wet food should I feed my cat?

Divide the daily calorie target by the calories in one can. A standard 3 oz can runs about 70 to 90 kcal (it's printed on the label). So a 10 lb neutered cat at roughly 260 kcal/day eats about three 3-oz cans, or one large 5.5 oz can plus one small. Feeding wet and dry together? Both draw from the same calorie budget.

How much dry food does a cat need?

Dry cat food usually runs 350 to 450 kcal per cup, so a typical indoor cat needs somewhere around half to two-thirds of a cup per day. That's far less than most scoops pour. Weigh it once with a kitchen scale and you'll know exactly what your cat's portion looks like.

How many calories should my cat eat to lose weight?

The standard starting point is 0.8 × RER calculated at the cat's ideal weight, not the current one. Cats are different from dogs here in one important way: crash-dieting a cat can trigger hepatic lipidosis, a dangerous liver condition. Weight loss should be slow (about 1 to 2% of body weight per week) and supervised by your vet.

How much should a kitten eat?

Kittens need about 2.5 × RER, and many vets simply recommend free-feeding a growth-formulated kitten food for the first several months. If you portion instead, recalculate every couple of weeks. Growth changes the math fast, and a kitten who suddenly eats less deserves a vet call.

Why does my cat always act hungry?

Begging is learned behavior more often than real hunger. Judge by the body instead: you should feel ribs easily under a light fat layer and see a waist from above. If your cat is gaining on the calculated portion, trim it about 10% and recheck in a month. Persistent ravenous appetite with weight loss is a vet visit, since it can signal hyperthyroidism or diabetes.

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