Blog · 8 November 2026
How much should I feed my dog?
The short answer: a 10 kg neutered adult dog needs about 630 kcal a day, a 20 kg dog about 1,059 kcal, and a 40 kg dog about 1,781 kcal. The numbers come from the formula vets actually use — resting energy (RER) times a life-stage factor (MER) — not from the bag, which is written for an average dog that may not be yours. This page explains the formula, gives you the feeding chart by weight, and shows how to turn calories into cups, grams and a routine you can adjust.
The formula vets use: RER × MER
Vets start from the resting energy requirement (RER) — the calories a dog burns just staying alive at rest. The formula, from the WSAVA Global Nutrition Guidelines and the National Research Council, is RER = 70 × (body weight in kg)^0.75. The 0.75 exponent matters: a 40 kg dog does not need four times what a 10 kg dog needs, it needs about 2.8 times as much, because larger animals burn fewer calories per kilogram.
Then the RER is multiplied by a life-stage factor to get the maintenance energy requirement (MER) — the calories your dog actually needs each day. Puppies and nursing mothers have the highest factors; neutered adults and seniors the lowest. Our pet feeding calculator does exactly this calculation, and converts the result into cups and grams using your own food's kcal per cup.
MER factors by life stage
| Life stage | MER factor | Notes |
|---|---|---|
| Puppy, under 4 months | 2.0–3.0 × RER | Growth food; 3–4 meals a day |
| Puppy, 4–12 months | about 2.0 × RER | Large breeds need controlled calcium |
| Adult, neutered | 1.4–1.6 × RER | The default for most pet dogs |
| Adult, intact | 1.6–1.8 × RER | Neutering cuts needs by roughly 20% |
| Active / working dog | 2.0–2.5 × RER | Sporting, herding, heavy work |
| Senior, low activity | 1.2–1.4 × RER | Watch weight — seniors gain easily |
| Weight loss | 1.0 × RER | Feed to the target weight, not the current one |
Factors: WSAVA Global Nutrition Guidelines and AAHA Weight Management Guidelines. Worked example: a 10 kg neutered adult — RER = 70 × 10^0.75 ≈ 394 kcal; × 1.6 = about 630 kcal/day.
Dog feeding chart by weight
Daily calories for a neutered adult dog at normal activity (MER = 1.6 × RER). Cups assume a typical dry kibble at 360 kcal per cup — check your own bag, because brands vary from about 300 to 400 kcal per cup.
| Dog's weight | RER (kcal/day) | Daily food (kcal) | Kibble at 360 kcal/cup |
|---|---|---|---|
| 5 kg (11 lb) | 234 | 374 | about 1 cup |
| 10 kg (22 lb) | 394 | 630 | about 1¾ cups |
| 15 kg (33 lb) | 534 | 854 | about 2⅓ cups |
| 20 kg (44 lb) | 662 | 1059 | about 3 cups |
| 25 kg (55 lb) | 783 | 1252 | about 3½ cups |
| 30 kg (66 lb) | 897 | 1436 | about 4 cups |
| 40 kg (88 lb) | 1113 | 1781 | about 5 cups |
The same formula works for cats — a 4.5 kg neutered adult cat: RER ≈ 216 kcal, × 1.2 = about 260 kcal/day. See how old is my cat in human years for the cat age side of the same story.
From calories to the bowl
Divide the daily calories by your food's density. At 360 kcal per cup, a 20 kg dog on 1,059 kcal gets about 2.9 cups a day; at 300 kcal per cup it would be 3.5 cups, and at 400 kcal per cup only 2.6. That is why the bag's chart is a rough guide at best — the same dog eats a different volume from every brand. The feeding calculator takes your food's own kcal per cup and gives you cups and grams in one step.
Split the daily amount into two meals for most adult dogs (three or four for puppies under 6 months). Keep treats under 10% of the daily calories — for a 630 kcal dog that is 63 kcal, roughly two small biscuits. Treats are the quiet way most dogs drift overweight: the main meals are measured, the extras are not.
Adjust from body condition, not appetite
The chart gives a starting point, not a prescription. The check that matters is the body condition score (BCS), the 1–9 scale vets use: at the ideal 4–5, you can feel the ribs easily without seeing them, there is a visible waist from above, and an abdominal tuck from the side. Weigh your dog every 2–4 weeks and move the food by about 10% at a time — less if the ribs are disappearing, more if they are showing. If your dog is overweight, calculate from the target weight, not the current one: feeding for the current weight simply maintains the excess.
Age changes the number too. Puppies need two to three times their resting energy; seniors need less than they did at five. If you are working out where your dog sits in life, the dog age calculator converts age to human years with the AKC size chart, explained in how old is my dog in human years.
Quick answers
How many calories does a 10 kg dog need a day?
About 630 kcal if neutered and moderately active — RER 394 × 1.6. That is about 1¾ cups of a 360 kcal/cup kibble, split into two meals.
How many cups of food should I feed my dog?
Divide the daily calories from the chart above by your food's kcal per cup (printed on the bag). A 20 kg dog needs about 1,059 kcal — 2.9 cups at 360 kcal/cup, 3.5 cups at 300, 2.6 cups at 400.
Should I feed my dog once or twice a day?
Twice a day for most adults — it steadies blood sugar and digestion, and large, deep-chested breeds fed once a day carry a higher bloat risk. Puppies under 6 months do better on three or four smaller meals.
How much should I feed a puppy?
About 2–3 × RER for puppies under 4 months, about 2 × RER from 4–12 months, on a food made for growth. A 10 kg puppy at 2.5 × RER needs roughly 984 kcal a day — far more per kilogram than an adult. Ask your vet before changing a large-breed puppy's diet, because calcium and growth rate matter as much as calories.
Sources
- WSAVA Global Nutrition Committee — Global Nutrition Guidelines and toolkit: RER = 70 × kg^0.75 and the MER life-stage factors.
- AAHA Weight Management Guidelines — body condition scoring and the 10% treat rule; the weight-loss factor of 1.0 × RER on target weight.
- National Research Council, Nutrient Requirements of Dogs and Cats (2006) — the energy requirement basis behind RER. See our About & Sources page for the full list.
Disclaimer: General guidance only, not veterinary advice. These are starting estimates from published veterinary formulas — individual dogs vary with breed, metabolism and health. If your dog is a puppy, pregnant or nursing, diabetic, or has kidney, thyroid or joint disease, ask your vet before changing the diet. If your dog is losing or gaining weight unexpectedly, see a vet.