How Many Calories Does a Dog Need? RER and MER Explained
Updated July 2026
A 30 lb neutered adult dog needs about 800 kcal a day; a 70-pounder needs about 1,500. Every credible feeding chart (your vet's, the bag's, ours) gets to those numbers the same way, and the five minutes it takes to understand the math permanently changes how you read pet food marketing.
Step 1: RER, the resting energy requirement
RER is what your dog burns lying around existing: keeping warm, digesting, thinking about squirrels. The veterinary standard formula is:
RER = 70 × (body weight in kg)0.75
The 0.75 exponent is why you can't scale portions linearly. A 10 lb dog needs about 218 kcal at rest; but a 100 lb dog needs around 1,225 kcal, not 2,180. Per pound, small dogs burn much hotter.
Step 2: MER, multiply by life stage
Maintenance energy requirement is RER times a factor for what the dog's body is doing:
| Life stage / goal | Factor | Why |
|---|---|---|
| Puppy under 4 months | 3.0 | Building a body from scratch |
| Puppy 4–12 months | 2.0 | Growth slowing, still substantial |
| Adult, spayed/neutered | 1.6 | Slightly slower metabolism post-alteration |
| Adult, intact | 1.8 | Hormones keep the furnace higher |
| Senior / low activity | 1.4 | Less lean mass, less movement |
| Weight loss | 1.0 × ideal weight | Feed the dog you want, not the dog you have |
| Working / sporting | 2.0–5.0 | Sled dogs top the scale |
Worked example
A 60 lb (27.2 kg) neutered adult Lab:
- RER = 70 × 27.20.75 ≈ 835 kcal
- MER = 835 × 1.6 ≈ 1,336 kcal/day
- On a 380 kcal/cup kibble: 1,336 ÷ 380 ≈ 3½ cups a day, or 1¾ cups twice daily.
Quick reference: daily calories by weight (neutered adult)
| Weight | kcal/day | Weight | kcal/day |
|---|---|---|---|
| 5 lb | ~205 | 50 lb | ~1,165 |
| 10 lb | ~350 | 60 lb | ~1,335 |
| 20 lb | ~585 | 70 lb | ~1,500 |
| 30 lb | ~795 | 80 lb | ~1,660 |
| 40 lb | ~985 | 100 lb | ~1,960 |
Why individual dogs vary ±25%
Metabolism, coat, climate, lean mass and neuter timing all move the number. That's why the pros treat the formula as a starting dose and titrate with body condition scoring: ribs palpable with light pressure, waist visible from above, abdominal tuck from the side. Check every couple of weeks; adjust portions 10% at a time. The formula gets you to the neighborhood; body condition finds the house.
Use the tools
Run the numbers for your dog on the main dog food calculator. Growing dogs: puppy feeding calculator (3× / 2× RER by age). Breed starting charts: feeding by breed. Formula sources and limits: About & methodology (NRC / WSAVA / AAHA framing).