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Dog Calorie Calculator
How many calories does your dog actually need? This calculator uses the resting energy (RER) formula and life stage factors from the Merck Veterinary Manual, and adjusts for age and neuter status.
How Calorie Needs Change Through Life
Puppies
Puppies need more calories per pound than adults, and the most when they are youngest: the Merck Veterinary Manual gives about 3 times resting energy under 4 months and 2 times after. Needs depend on age and expected adult size, so ask your vet for a target and follow your puppy food's label. Feed 3-4 times daily until 6 months, then transition to twice daily.
Adults
Maintenance needs settle in adulthood: Merck gives 1.8 times resting energy for intact adults, 1.6 for spayed or neutered, and 1.4 for dogs that gain weight easily. Working and sport dogs vary too widely for one formula (AAHA gives 1.6 to 11 times), so ask your vet.
Seniors
A dog is senior in roughly the last quarter of its expected lifespan, so a small breed may reach it around 12 and a large breed around 7 or 8. Calorie needs generally drop with age, but there is no fixed percentage, and some seniors lose weight and muscle and need more. Ask your vet for a target and check weight and muscle every 2 to 4 weeks.
Frequently Asked Questions
What is RER and why does this calculator use it?
RER stands for Resting Energy Requirement -- the number of calories a dog needs just to maintain basic body functions at rest (breathing, circulation, organ function). It's calculated as 70 × (body weight in kg)^0.75. This formula is used by veterinary nutritionists and is more accurate than simple per-pound multipliers, especially for very small or very large dogs. The RER is then multiplied by a life stage factor. This calculator uses the Merck Veterinary Manual's factors: 3 for puppies under 4 months, 2 from 4 months until fully grown, 1.8 for intact adults, 1.6 for spayed or neutered adults and 1.4 for adults that gain weight easily.
Why do neutered dogs need fewer calories?
Spayed and neutered dogs tend to gain weight more easily on the same food. The Merck Veterinary Manual reflects this with a lower starting factor: 1.6 times resting energy for spayed or neutered adults against 1.8 for intact adults, which is about 11% less. Weigh your dog after surgery and adjust.
My dog is on the bag's feeding guide. Is that accurate?
A feeding guide on a bag is written for a typical dog, so it can't account for your dog's neuter status, activity or metabolism. Use this calculator as a starting point, then weigh your dog every 2 to 4 weeks and adjust the amount up or down to keep a healthy body shape.
How many calories are in a cup of dog food?
It varies by brand and formula, so use the figure on your own food. Look for the "Calorie content" line: in the US, AAFCO rules require it in kcal per kg and per cup or can (for example, 445 kcal/cup), and most foods sold in Canada show it too. Using the wrong number will throw off your portions significantly. Our dog food calculator turns your dog's calorie target into cups, cans or grams using that figure.
Should I use my dog's current weight or ideal weight to calculate calories?
If your dog is overweight, use their ideal target weight, not their current weight. Feeding to current weight would maintain the excess weight. If your dog is underweight, use their target weight as well to provide the calories needed to gain appropriately. Your vet can confirm a target weight if you're unsure.
