How it's worked out
First the resting energy requirement (RER): 70 × body weight in kg to the power 0.75. That's what the body burns at rest. Then a factor for life stage and activity gives the daily target. These are the starting factors vets commonly use:
| Pet | Situation | × RER |
|---|---|---|
| Dog | Puppy under 4 months | 3.0 |
| Dog | Puppy 4–12 months | 2.0 |
| Dog | Adult, neutered / intact | 1.6 / 1.8 |
| Dog | Couch potato or senior | 1.3–1.4 |
| Dog | Active / working | 2.0 / 3.0 |
| Dog | Weight loss (at ideal weight) | 1.0 |
| Cat | Kitten | 2.5 |
| Cat | Adult, neutered / intact | 1.2 / 1.4 |
| Cat | Indoor, not very active | 1.0 |
| Cat | Weight loss (at ideal weight) | 0.8 |
Every pet is different, so weigh them every few weeks. If they gain, feed about 10% less; if they lose without trying, feed a bit more and check with your vet.