Dog daily calorie needs

How it works

You start from the resting metabolism (RER = 70 × weight^0.75) and multiply it by a factor depending on age, neutering and activity, getting the daily need (MER).

Note

It's a rough estimate: real needs vary from dog to dog. For diets and weight issues always follow your vet's advice.

Why the exponent is 0.75 and not 1

This is the part of the sum that looks arbitrary and isn't. Requirements don't grow in proportion to weight: a 40-kilo dog doesn't eat twice what a 20-kilo one eats, it eats about 70% more. The reason is that heat is lost from the surface and surface grows more slowly than volume, so the smaller the animal, the more calories it needs per kilo. It's the same law that holds for every mammal, from the mouse to the elephant, and it's why a chihuahua is a furnace and a great dane is surprisingly frugal.

The factor counts as much as the weight

Resting metabolism (RER) is what's needed to stay still; the real requirement (MER) is the RER multiplied by a coefficient, and that coefficient varies a lot. Neutering lowers it by about 20-30%, and that's the main reason a dog puts on weight after the operation: the food stayed the same and the requirement fell. A growing puppy sits at two or three times the RER; an elderly and inactive dog drops below average; a working or sporting dog can reach five times.

The estimate is a starting point, not a verdict

Between two dogs of the same weight, age and lifestyle the real requirement can differ by twenty per cent: it depends on breed, muscle mass, coat, the temperature they live in. No formula knows that. The right way to use this number is to start there for two or three weeks, then weigh the animal and look at it, and adjust by 10% at a time.

If the aim is weight loss, what matters is that it's slow: too rapid a drop is dangerous, and in cats it can cause a serious liver problem. It's something to set up with the vet, not to improvise by cutting the bowl.

Nearby tools

To turn calories into grams of kibble there is Daily kibble amount, and for cats Cat calorie needs. For water Water for dogs and cats and for foods to avoid Foods dangerous for pets.