Dog food calculator: calories and portions per day
A starting estimate from your dog's weight and life stage, turned into cups or grams of food.
To work out how much to feed your dog, start with the RER: 70 x body weight in kg to the power of 0.75. Multiply it by a factor for life stage and neuter status to get the maintenance energy requirement (MER), which is the daily calorie estimate. Then divide by the calories on the food label to get cups or grams.
BowlMath is mainly a cat food site. Dogs need different factors, so this page has its own math. For a cat, use the cat calorie calculator.
How does the dog food calculator work?
The factor depends on life stage, neuter status and how easily your dog gains weight. The calculator uses these factors from the Merck Veterinary Manual:
| Your dog | Factor | Source |
|---|---|---|
| Puppy under 4 months | 3 x RER | Merck |
| Puppy 4 to 12 months | 2 x RER | Merck |
| Adult, not neutered | 1.8 x RER | Merck (AAHA range 1.6 to 1.8) |
| Adult, spayed or neutered | 1.6 x RER | Merck (AAHA range 1.4 to 1.6) |
| Adult that gains weight easily or is not very active | 1.4 x RER | Merck (AAHA range 1.0 to 1.2) |
| Weight loss | 1 x RER at the ideal weight | AAHA |
The American Animal Hospital Association (AAHA) gives similar ranges in its 2021 guidelines. AAHA says these factors are general starting points, that dogs who move little may need less, and that you should adjust by body weight and body condition score. Its range for inactive dogs is lower than the 1.4 used here, so a quiet dog may need less than the calculator shows.
Worked example: a 20 kg neutered adult dog
For a spayed or neutered adult dog that weighs 20 kg (44 lb):
With a dry food that has 350 kcal per cup, that is about 3 cups a day, or 1 1/2 cups per meal over two meals. With a food labelled 3,600 kcal per kg, it is about 295 g a day, 150 g per meal. The calculator rounds the daily cups to the nearest quarter cup and then splits them over the meals, and rounds grams to the nearest 5 g, so a kitchen scale is the more exact choice.
How much should I feed a dog that needs to lose weight?
For weight loss, the AAHA guidelines work from the ideal weight, not the current one: 1.0 x RER at the ideal weight. For a 25 kg dog whose vet suggests an ideal weight of 20 kg, that is about 660 kcal a day.
Agree the target and the plan with your vet before you start. Weigh your dog every 2 weeks so you can see whether the plan is working, and let your vet know if your dog seems hungry, tired or unwell.
Which dogs need a number from the vet?
The factors are averages, and individual dogs can differ a lot. Please ask your vet for a calorie target instead of using this estimate if your dog:
- is a very active or working dog
- is pregnant or nursing
- has a medical condition or eats a prescription diet
- is losing or gaining weight without a change in food
How do I know if the amount is right?
Weigh your dog once a month at the same time of day and write the number down. If your dog keeps gaining, or keeps losing when it should not, change the amount in small steps and weigh again a month later. Treats and table scraps count too, so include them in the daily total.
Thinking about fresh dog food? The Farmer's Dog vs Ollie cost per day puts each brand's own published prices side by side.
Questions
How many calories does my dog need a day?
A rough starting point is 70 x weight in kg to the power of 0.75, times 1.6 for a spayed or neutered adult. For a 20 kg dog that is about 1,060 kcal a day. Check with your vet, because individual dogs differ a lot.
How many cups of dog food should I feed a day?
Divide the daily calories by the kcal per cup printed on the bag. If the bag lists only kcal per kg, choose kcal per kg in the calculator to get grams instead.
Do neutered dogs need fewer calories?
Usually, yes. The Merck Veterinary Manual uses 1.6 x RER for neutered adult dogs and 1.8 x RER for intact adults. Weigh your dog after neutering and adjust the amount if the weight creeps up.
Does this work for puppies?
It gives a rough starting point: 3 x RER under 4 months and 2 x RER from 4 to 12 months. Puppies grow fast, so weigh them often and ask your vet how much to feed, especially for large breeds.
Sources
- Merck Veterinary Manual: Daily maintenance energy requirements for dogs and cats (table)
- AAHA: 2021 nutrition and weight management guidelines, Box 1 energy requirement calculations
Related
Estimate only. Check with your vet. Not veterinary advice. These are starting estimates and individual dogs can differ a lot. Very active or working dogs, pregnant or nursing dogs, puppies and dogs with a medical condition need their vet's number.