Dog Calorie Calculator

RER = 70 × (body weight in kg)^0.75; calories a day = RER × the factor for the life stage; the low and high figures are RER × each end of that stage's factor range

weight

The dog's body weight in kilograms. The 0.75 power is applied to it, so a dog twice as heavy needs about 1.7 times the calories, not twice

rer

Resting energy requirement, from the 70 × kg^0.75 equation. It is the same figure at every life stage, which is what makes it the number to compare between dogs

factor

The multiplier for the life stage, from 1.0 for an inactive adult up to 11.0 for a working dog on a heavy day. Most stages are published as a range rather than as one number

caloriesPerDay

Calories a day at the middle of the factor range, rounded to a whole kilocalorie. The two ends of the range are reported as well, because some of the ranges are more than twice as wide as others

There are two reasons to reach for a dog calorie calculator. The first is portioning. Feeding amount on a bag of food is printed for a band of weights and usually for an unneutered adult, so a dog's own calorie needs can sit well below the bag's suggestion, and following the bag is one of the commonest routes to an overweight dog. The second is checking a feeding routine that is already in place: if the weight is creeping up on the amount that is being fed, this is the arithmetic to bring to the vet. The factor table covers the stages that move the answer most, and a puppy feeding amount is the one people get wrong most often, because a puppy under four months needs three times its resting energy requirement and a puppy past four months needs two.

1. A 20 kg neutered adult dog

   1. Resting energy requirement: 70 × 20^0.75 = 70 × 9.457 = 662.0 kcal
   2. The neutered adult factor is 1.4 to 1.6, so the middle is 1.5
   3. 662.0 × 1.5 = 993 kcal a day
   4. The ends of the range: 662.0 × 1.4 = 927 and 662.0 × 1.6 = 1059

   This is the default on the page, so it is also the first thing a reader sees. The range is narrow here — 927 to 1059, about 14% either side — which is typical for an adult dog at a stable weight.

2. The worked example in the AAHA guidelines: a 10 lb, 4.5 kg neutered adult

   1. Resting energy requirement: 70 × 4.5^0.75 = 70 × 3.090 = 216.3 kcal
   2. The guidelines print 216 for this step, having rounded before multiplying
   3. 216.3 × 1.4 = 302.8, which rounds to 303 kcal a day
   4. The guidelines print 302, so the two differ by one kilocalorie

   The one-kilocalorie difference is worth reading rather than smoothing over. The guidelines round the resting energy requirement to 216 before multiplying; this page keeps the unrounded 216.3. Both are correct to the precision either one claims, and the resting energy requirement is shown on its own row so you can see exactly where the difference comes from.

3. An 8 kg puppy, still under four months old

   1. Resting energy requirement: 70 × 8^0.75 = 70 × 4.757 = 333.0 kcal
   2. Under four months the factor is 3.0, a single number rather than a range
   3. 333.0 × 3.0 = 999 kcal a day
   4. All three calorie rows are therefore the same figure

   A puppy this age eats about three times what its resting energy requirement suggests, which is roughly twice what the same dog will eat as an adult. This is the stage where guessing goes wrong most often, and where a bag of food is least helpful, because puppy food is printed for a wide band of expected adult weights.

This is an estimate built on a population average, not a prescription for one dog. Two dogs of the same weight and the same life stage can differ by 20% in what keeps their weight steady, so treat the figure as a starting point and adjust it against the dog. Nursing is not in the table: the AAHA guidance gives lactation as 3.0 up to 6.0 or more, which depends on the size of the litter and the week of nursing, and this page has no input for either. The factors are for healthy dogs. A dog that is ill, recovering from surgery, or being treated for cancer has different energy needs and should be fed to a vet's plan. The resting energy requirement is also not the right basis for a critically ill patient, where the vet will use an illness factor instead. Finally, the answer is in kilocalories, not grams: turning it into a portion size needs the calorie density printed on the food, and that is a different calculation.

How many calories should my dog eat a day?

Multiply the resting energy requirement by a factor for the life stage. The resting energy requirement is 70 × body weight in kilograms to the power 0.75, which for a 20 kg dog is 662 kcal; a neutered adult factor of 1.4 to 1.6 then puts the daily figure between 927 and 1,059 kcal. That is a starting point rather than a target: feed it for a fortnight and adjust by what the dog's weight does.

What is the resting energy requirement?

It is the energy a dog would burn lying still in a thermoneutral room, fasted — the cost of breathing, pumping blood and keeping cells alive, with nothing added for walking, growing or keeping warm. It is calculated as 70 × body weight in kilograms raised to the power 0.75. Because it holds no activity or life-stage term, it is the one figure that can be compared directly between two dogs, and it is the number a vet reaches for first when planning how much to feed an in-patient.

Why does the calculator give three calorie figures instead of one?

Because the published factors are ranges. A neutered adult is 1.4 to 1.6 times the resting energy requirement, and heavy work in a sled dog is 5.0 to 11.0 — more than twice as wide. A single number would make the widest stage look as precise as the narrowest, so the middle of the range is shown as the headline and both ends underneath it. If the two ends are far apart, the honest reading is that the factor table does not pin your dog down and the weight chart should.

Should a neutered dog eat less than an unneutered one?

Yes, slightly. The factor for a neutered adult is 1.4 to 1.6 and for an intact adult 1.6 to 1.8, so neutering moves the estimate down by roughly 10 to 15%. That is a smaller effect than most people expect, and a much smaller one than the change in appetite and activity that usually follows neutering — which is why the weight chart, not the factor, is what catches the gain.

Can I use this for a puppy or for a working dog?

Both are in the table, and both need care. A puppy under four months has a factor of 3.0 and a puppy from four months to adult 2.0; these are the highest factors most owners will meet, and they change with age, so the figure has to be recalculated as the puppy grows. For a working dog the range is wide by design — light work is 1.6 to 2.0, moderate 2.0 to 5.0 and heavy 5.0 to 11.0 — because the energy cost of a working day depends on terrain, temperature and how hard the dog actually pulls, none of which a calculator can see.

• 2021 AAHA Nutrition and Weight Management Guidelines, Box 1: energy requirements — American Animal Hospital Association
• Nutritional Requirements and Related Diseases of Small Animals — MSD Veterinary Manual
• Global Nutrition Guidelines — World Small Animal Veterinary Association
• How Much Water Does a Dog Need? — PetMD (reviewed by Jennifer Larsen, DVM, PhD, DACVN)