How this calculator works
Veterinary nutrition starts with the Resting Energy Requirement (RER) — the calories a cat burns at complete rest: RER = 70 × (body weight in kg)0.75. Real cats groom, patrol the house and occasionally sprint at 3 a.m., so the RER is multiplied by a life-stage factor to get the Maintenance Energy Requirement (MER) — the daily number this tool reports.
| Life stage | Factor × RER |
|---|---|
| Weight loss (vet-supervised) | 0.8 |
| Inactive / gains weight easily | 1.0 |
| Senior, low activity | 1.1 |
| Neutered adult | 1.2 |
| Intact adult | 1.4 |
| Kitten, 4–12 months | 2.0 |
| Kitten, under 4 months | 2.5 |
Cats need less food than most owners think
A typical 10 lb indoor neutered cat needs only about 200 kcal per day — half a cup of many dry foods, or roughly two 3-oz cans of wet food. Free-feeding from a bottomless bowl of calorie-dense kibble is how most indoor cats end up overweight, and overfeeding is widely considered the number one nutrition problem in pet cats. Measured meals, not a full bowl, are the single most effective habit change.
Signs you've got the amount right
You should be able to feel your cat's ribs under a thin fat layer, and see a slight waist when looking down from above. Weigh your cat monthly (step on a scale holding the cat, then subtract yourself, or use a baby scale). Steady weight in an adult cat means the target is working; adjust in 10% steps rather than big jumps, and never crash-diet a cat — rapid weight loss risks hepatic lipidosis.
Frequently asked questions
How many calories does a cat need per day?
Most healthy adult cats need between 180 and 280 kcal per day. Vets start with the Resting Energy Requirement: RER = 70 × (weight in kg)^0.75, then multiply by a life-stage factor — 1.2 for a typical neutered adult. A 10 lb indoor neutered cat needs only about 200 kcal/day.
Why does my cat need so few calories?
Cats are small and most indoor cats are fairly sedentary. 200 kcal is roughly half a cup of typical dry food or two 3-oz cans of wet food — much less than many owners expect, which is why overfeeding is so common.
Do kittens really need double the calories?
Per pound of body weight, yes. Growing kittens use 2 to 2.5 times their resting energy requirement to build tissue. Feed a food labeled for growth (kitten or all-life-stages) and let a young kitten eat to appetite unless your vet says otherwise.
My cat is overweight. Can I just cut the food in half?
No — sudden severe restriction is dangerous for cats. Overweight cats that stop eating or lose weight too fast can develop hepatic lipidosis, a life-threatening liver condition. Weight loss should target about 0.8 × RER of the cat's ideal weight and be supervised by a vet.