There’s no exact number for any dog. Needs vary with age, size, activity, neutering and the individual, so every method gives a starting point that you then adjust.
1. Start with the pack
The feeding guide on the pack is intended as a starting point, not a fixed rule.[1] Weigh portions rather than using a scoop, and count treats and chews in the day’s food.
2. Adjust by body condition, not the scales alone
Feed to keep your dog at an ideal body condition.[1] Vets use a 9-point body condition score; 4 to 5 is ideal.[3] At 5, you can feel the ribs without excess fat over them, and see a waist behind the ribs from above.[4] The WSAVA chart shows each score with pictures.
If your dog is gaining weight, feed a little less; if losing, a little more. Change amounts gradually and check again after a few weeks.
3. The calorie formula vets use
Vets often start from the resting energy requirement (RER): 70 × body weight in kg to the power of 0.75.[2] A 10 kg adult dog’s RER is about 400 kcal a day.[2] Daily needs are then RER multiplied by a factor for life stage and activity. Ohio State University’s veterinary nutrition service gives, for example[2]:
| Dog | Daily need |
|---|---|
| Neutered adult | 1.6 × RER |
| Intact adult | 1.8 × RER |
| Inactive or prone to weight gain | 1.2–1.4 × RER |
| Active or working | 2.0–5.0 × RER |
| Puppy, up to 4 months | 3.0 × RER |
| Puppy, 4 months to adult | 2.0 × RER |
Individual dogs can differ from these calculations by as much as 50%, which is why body condition matters more than the maths.[2] European guidelines make the same point: calculated amounts are only a starting point.[3]
To turn calories into grams, divide by the food’s energy per 100 g and multiply by 100. If the label doesn’t give the energy, you can’t do this reliably, so use the pack’s guide.
Why it matters
In PDSA’s 2023 PAW Report, UK vet professionals estimated on average that 46% of dogs are overweight or obese.[5] Vet records give a lower figure: a Royal Veterinary College study found 7.1% of dogs under vet care were recorded as overweight in a year. But the researchers said that’s likely just the tip of the iceberg, as weight isn’t always recorded.[6]
How this site estimates it
When you add your dog, we use RER × 1.2 (less active adult), 1.45 (typical adult), 1.75 (very active adult) or 2.1 (puppy), show a ±10% range, and convert it to grams and cost per day for each food. It’s a starting estimate. Young puppies under about 4 months may need more, so follow the pack and your vet. More on our method.
Sources
- Calculating how much to feed, UK Pet Food
- Companion Animal Nutrition Support Service, Ohio State University Veterinary Medical Center
- Nutritional Guidelines for Complete and Complementary Pet Food (2025), FEDIAF
- Body Condition Score chart (dogs), WSAVA Global Nutrition Committee
- PAW Report 2023: dogs, PDSA
- RVC study reveals extent of dog obesity crisis in the UK (23 March 2021), Royal Veterinary College, VetCompass
This guide is general information, not veterinary advice. Spotted an error? Tell us.