Estimate how many calories your cat needs each day and how much wet or dry food that is, based on its weight and life stage.
Quick answer: A cat's daily calories come from its resting need — 70 × (weight in kg)0.75 — multiplied by a life-stage factor (about 1.2 for a typical neutered adult). Divide by the calories in the food to get the portion. A 10 lb neutered adult cat needs roughly 260 kcal a day.
This is a general starting-point estimate, not veterinary advice. Ideal intake varies with age, health and body condition. Ask your vet, especially for kittens, pregnant or nursing cats, or any cat with a health condition. Never crash-diet a cat — rapid weight loss can cause serious liver disease.
Split into two or more small meals, or feed to a measured daily total. Adjust over a few weeks based on body condition.
How much to feed a cat starts with how many calories it burns, which depends on its weight and life stage. Vets estimate the resting energy requirement (RER) and scale it up for maintenance (MER). Once you have the daily calories, the amount of food is that figure divided by the calories in the food — so a rich wet food needs a smaller portion than a light one.
How the calculation works
RER (kcal/day) = 70 × (body weight in kg)0.75 MER (kcal/day) = RER × life-stage factor Amount to feed = MER ÷ calories per unit of food
Typical life-stage factors are about 1.2 for a neutered adult, 1.4 for an intact adult, 0.8 for weight loss, 1.0 for weight-gain-prone cats and around 2.5 for growing kittens. The calories in the food are on the label as "kcal per can", "kcal/kg" or "kcal per cup".
Worked example
A 10 lb cat is 4.54 kg. RER = 70 × 4.540.75 ≈ 70 × 3.11 ≈ 217 kcal. For a neutered adult, MER = 217 × 1.2 ≈ 261 kcal a day. If a can holds 180 kcal, that is 261 ÷ 180 ≈ 1.4 cans a day.
Adjust for the individual cat
These are averages; individual cats vary. Weigh your cat, feel its body condition (ribs easy to feel, a visible waist from above), and adjust over two to three weeks. Treats should stay under 10% of daily calories. Kittens, pregnant and nursing cats have higher needs. Overweight cats must lose weight slowly and under veterinary supervision to avoid hepatic lipidosis.
Frequently asked questions
How many calories does my cat need per day?
Roughly 70 × (weight in kg)^0.75 for resting, times a life-stage factor of about 1.2 for a normal adult. A 10 lb cat needs around 260 kcal a day.
How much wet food should I feed my cat?
Divide the daily calories by the calories per can. If your cat needs 260 kcal and a can is 180 kcal, feed about 1.4 cans a day.
Should cats eat wet or dry food?
Both can be complete and balanced. Wet food adds water, which helps urinary health; the calorie maths works the same either way — just use the label's calories.
My cat is overweight — how do I help it lose weight?
Use the weight-loss factor for a slow reduction and cut treats, but always plan feline weight loss with your vet, as cats can develop serious liver disease if they lose weight too fast.
For general information only — not veterinary advice. Consult your vet for feeding plans, weight management and any cat with special needs.
Written by the CalcPine team · Reviewed for accuracy · Last updated 24 July 2026 · Method: RER = 70 × kg^0.75; MER = RER × life-stage factor; portion = MER ÷ food calories.
