Estimate your cat’s daily calories. This free cat calorie calculator uses the vet RER/MER formula with weight and life-stage/activity to give a daily feeding target and per-meal amount.
This gives a general daily calorie estimate for a healthy adult cat using standard veterinary formulas. Needs vary with age, health and activity, and cats are prone to obesity and to serious problems from crash dieting. For weight loss, kittens, pregnancy or any medical condition, follow your veterinarian’s guidance.
Your cat
kg
Enter your cat’s weight and pick the option that fits. The estimate uses the resting energy requirement (RER) scaled by a life-stage and activity factor.
Daily calories
—
Enter your cat’s weight
Resting need (RER)
—
Daily need (MER)
—
Activity factor
—
Per meal (×2/day)
—
Formula: RER = 70 × (weight in kg)^0.75, then daily calories (MER) = RER × activity factor. A 4.5 kg neutered adult cat needs roughly 220–260 kcal a day. Never crash-diet a cat — rapid weight loss can cause serious liver disease.
Use this free cat calorie calculator to estimate how many calories your cat needs each day. Enter their weight and life stage to get a daily feeding target.
What this cat calorie calculator does
A cat calorie calculator estimates daily energy needs using the standard veterinary RER and MER formulas, adjusted for whether your cat is neutered, indoor, growing or losing weight.
So a 4.5 kg neutered adult cat needs roughly 220–260 calories a day; indoor cats are often a little lower.
Activity factors for cats
Cat
Factor (× RER)
Weight loss
0.8
Indoor / inactive
1.0
Neutered adult
1.2
Intact adult
1.4
Kitten (growing)
2.5
Turning calories into food
Check the kcal per can or per cup on your cat food, then divide the daily target by that to find how much to feed. Many cats do well with measured meals rather than free-feeding.
A caution on cat weight loss
Never crash-diet a cat. Rapid weight loss can trigger hepatic lipidosis (fatty liver disease), which is serious. Any weight-loss plan should be gradual and supervised by your vet.
How to use the cat calorie calculator
Enter your cat’s weight in kg or lb.
Choose life stage / activity.
Read the daily calories and per-meal amount.
Cat Calorie FAQ
How many calories does my cat need?
Multiply resting needs by an activity factor: RER = 70 × kg^0.75, then × 1.2 for a typical neutered adult. A 4.5 kg cat needs about 220–260 calories a day.
How much should I feed my cat?
Divide the daily calorie target by the kcal per can or cup on your cat food, then split it into measured meals.
Do indoor cats need fewer calories?
Often yes. Indoor, less-active cats use a lower factor (around 1.0 × RER), so they need fewer calories than active cats of the same weight.
How many calories does a kitten need?
Kittens need much more for growth — about 2.5 × RER — tapering toward adult levels as they mature.
Can I put my cat on a diet?
Only gradually and with veterinary guidance. Rapid weight loss in cats can cause hepatic lipidosis, a dangerous liver condition.
Is the cat calorie calculator free?
Yes, this cat calorie calculator is completely free, needs no sign-up, and gives instant results in your browser.
