What is the Dog Food Calculator?
The Dog Food Calculator estimates how much food your dog should eat each day. It starts from the dog's body weight to find its Resting Energy Requirement (RER), multiplies by an activity/life-stage factor to get the daily calorie need, then divides by your food's calorie density to convert calories into grams. This is a universal, science-based method used by veterinarians worldwide.
How to use it
Enter your dog's weight in kilograms, choose the activity level or life stage that best matches your dog, and enter the energy density of the food (look on the bag — often shown as "kcal/kg"; divide by 1000 to get kcal per gram, e.g. 3,500 kcal/kg = 3.5 kcal/g). The calculator returns the recommended grams per day, plus per-meal portions for twice-daily feeding.
The formula explained
The RER uses the metabolic scaling law $$RER = 70 \times W^{0.75}$$. Body energy use does not scale linearly with weight, so the 0.75 exponent gives a fairer estimate across small and large dogs. The Maintenance Energy Requirement (MER) multiplies RER by an activity factor: roughly 1.0 for neutered low-activity adults, 1.4 for normal adults, 1.6 for active dogs, and 2–3 for growing puppies. Finally, the daily food in grams is given by $$\text{Food (g)} = \frac{RER \times A}{k}$$ which expands to $$\text{Food (g)} = \frac{70 \times W^{0.75} \times A}{k}$$
Worked example
A 15 kg normal adult dog (factor 1.4) eating 3.5 kcal/g food: $$RER = 70 \times 15^{0.75} = 70 \times 7.622 \approx 533.5 \text{ kcal}$$ $$MER = 533.5 \times 1.4 \approx 746.9 \text{ kcal/day}$$ $$\text{Food} = 746.9 \div 3.5 \approx 213.4 \text{ g per day}$$ or about 107 g per meal.
FAQ
Is this a substitute for a vet? No. It's a starting estimate. Adjust based on your dog's body condition and consult your veterinarian for health conditions.
How do I find kcal per gram? Take the "kcal/kg" value from the food label and divide by 1,000.
How often should I feed? Adults typically eat twice daily; puppies often need 3–4 smaller meals.
