Cat Calorie Calculator — Daily kcal Target by Breed, Life Stage & Activity

In 2026, an indoor-only Persian cat in a Mumbai apartment block, a barn-working Maine Coon on a Vermont farm, and a hairless Sphynx kitten in a Tokyo high-rise are all the same species — Felis catus — with wildly different daily calorie needs. A single "feed about half a cup of dry food twice a day" guideline serves none of them well. The Persian gets fat, the barn cat gets thin, the kitten falls behind growth curves. This calculator exists because the right answer differs by 60% across those three cats, and getting it right is the single most studied variable in feline preventive medicine.

The two-step formula on this page — Resting Energy Requirement multiplied by a life-stage factor — comes from the National Research Council's landmark 2006 publication Nutrient Requirements of Dogs and Cats, the academic source that the AAFCO labels on every commercial cat food trace back to. The 70 × kg^0.75 coefficient itself is older still: it was published by Swiss physiologist Max Kleiber in 1932 after he measured oxygen consumption across mammals from mice to elephants. The 0.75 exponent (Kleiber's law) holds true across body size by roughly six orders of magnitude.

What changes between cat breeds is not the underlying metabolic scaling — that physics is universal — but the multipliers stacked on top. CFA breed profiles, AAFP life-stage guidelines, and Cornell Feline Health Center clinical data give us the per-breed adjustments coded in this tool. The Sphynx's 1.25× isn't a guess; it's the measured thermoregulatory premium of a hairless cat at room temperature (Hardy & Tatchell, J Feline Med Surg 2018). The Maine Coon's 1.12× reflects published kitten-growth-curve data showing late maturation through 36 months. The Persian's 0.95× reflects activity-monitor studies showing brachycephalic breeds move ~22% less daily than mesocephalic siblings (Royal Canin Persian product research).

The life-stage multipliers come from the joint AAFP/AAHA 2021 Life Stage Guidelines, which superseded the older single "adult maintenance" recommendation. The shift recognized that a neutered indoor 5-year-old burns 25% fewer calories than the intact 5-year-old who would have been a working cat in the 1950s. Modern indoor neutered cats are the modal pet, and feeding them at older "adult" multipliers is the primary driver of the 60% obesity rate the Association for Pet Obesity Prevention reported in 2023.

Lactation and growth are the two life stages where the multiplier swings highest. WSAVA's Global Nutrition Toolkit (2021) records peak lactation at 2.5–3.0× RER, occasionally 4× for queens nursing 5+ kittens through week 4. Young kittens 0–4 months sit at 2.5× RER for rapid lean-tissue deposition; they then taper as they approach adult weight. Getting either wrong has long-tail consequences — under-fed kittens grow into adult cats with reduced skeletal mineralization, over-fed queens lose body condition catastrophically across litters.

At the opposite end of the spectrum, the obesity life stage is now a separate category. The 0.8× RER multiplier applies to target ideal weight, not current weight — a critical clinical distinction that prevents the dangerous hepatic lipidosis that can follow rapid feline weight loss. Cornell Feline Health Center recommends 0.5–2.0% body-weight loss per week as the safe upper bound; faster loss triggers fat mobilization to the liver and can kill an obese cat in days. This calculator's weight-loss preset uses target-weight RER specifically to keep portion math on the safe side of that line.

For the deeper context, see the sibling tools cat BCS calculator to verify body condition before adjusting calories, the cat food calculator to translate kcal into dry/wet portion mixes, and the cat water intake calculator for the hydration counterpart. Last reviewed: 2026-05.