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Dog & Cat Calorie Calculator (RER/DER)

Estimate a dog's or cat's daily calorie needs from its body weight and life stage, using the standard veterinary RER/DER method, in metric or imperial units.

Resting energy requirement (RER)
394 kcal/day
Daily energy requirement (DER)
630 kcal/day

How it works

A pet's resting energy requirement (RER) — the calories burned at complete rest — is estimated with the standard veterinary allometric formula RER = 70 × weight(kg)^0.75, from the WSAVA's Global Nutrition Guidelines. The 0.75 exponent scales with body surface area rather than mass directly, which is what keeps the same formula accurate across the huge weight range between a kitten and a large dog.

Daily energy requirement (DER) — what the animal actually needs to eat day to day — multiplies that resting baseline by a life-stage/activity factor: DER = RER × factor. The factors offered (1.0 for weight loss up to 3.0 for a puppy or kitten under 4 months) are the commonly published veterinary bands for that purpose, not a computed figure — pick whichever best matches the animal.

The formula's exponent is calibrated for kilograms, so imperial entries are converted to metric before the calculation runs.

FAQ

Is this a substitute for veterinary advice?

No — this gives the same population-average starting estimate a vet would typically begin from, not an individualized prescription. An animal's actual needs vary with breed, metabolism, health conditions, and climate, so treat the result as a starting point to discuss with a vet or adjust from based on the pet's actual weight trend, not a fixed target.

Which life stage should I pick if my pet doesn't clearly fit one?

For a healthy adult that's neither gaining nor losing weight, 'Neutered/spayed adult' or 'Intact adult' (matching its actual status) is the right default — the growth and weight-management bands are specifically for puppies/kittens and animals on an active diet plan, not typical maintenance.

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