Feeding by weight starts with the RER formula — 70 × (body weight in kg)^0.75 — multiplied by a life-stage factor. The bag chart is a starting guess, not a prescription.
| Item | Detail |
|---|---|
| RER formula | 70 × (kg)^0.75 — the resting energy requirement |
| Neutered adult | RER × 1.6 |
| Intact adult | RER × 1.8 |
| Weight loss | RER × 1.0 (of ideal weight, never current weight) |
| Puppy (4–12 mo) | RER × 2.0, split into 2–3 meals |
Worked example: the 40 lb dog
40 lb = 18.1 kg. RER = 70 × 18.1^0.75 ≈ 722 kcal. Neutered adult: × 1.6 ≈ 1,155 kcal/day. At 390 kcal/cup, that is just under 3 cups — where most owners discover their “2 cups plus treats” routine has been quietly overfeeding. Our calculator does this math for any weight, and the treat budget sheet keeps snacks inside the total.
Adjust by body condition, not arithmetic
The formula is the start; the monthly body-condition score is the correction. Ribs should be feelable-not-visible, waist visible from above. Every score point off ideal adjusts calories by ~10%. Our 9-point BCS card and cup-conversion table close the loop.
FAQ
Do I feed for current weight or ideal weight?
Ideal weight for overweight dogs (× 1.0 factor); current weight for healthy dogs. Feeding an obese dog at current weight perpetuates the obesity.
How accurate are feeding charts on bags?
They assume intact, moderately active dogs. Neutered house pets typically need 15–20% less than charted.
Related reading: Calorie calculator · BCS card · All tools · Life-stage guides