Dog & Cat Food Portion Calculator
Calculate how much to feed your pet daily based on weight and activity level.
Results are estimates only — not a substitute for veterinary advice.
Advanced: custom food calories
How the food portion calculator works
This calculator uses the Resting Energy Requirement (RER) formula, which is the standard starting point used by veterinary nutritionists worldwide:
RER = 70 × weight_kg0.75
RER is the number of calories your pet needs simply to maintain basic body functions at rest — breathing, circulation, and cell repair. To account for daily activity, we multiply RER by an activity factor:
- Weight loss: 1.0× — just enough for maintenance without surplus
- Low activity: 1.2× — older dogs, brachycephalic breeds, indoor cats
- Moderate: 1.4× — the average adult dog or cat with daily walks
- High activity: 1.6× — working dogs, sporting breeds, very active pets
The resulting daily calorie number is then divided by your food's calorie density(kcal per cup or per 100g) to give the amount to feed. Default values assume a typical dry kibble at 350 kcal/cup. Check your bag's nutrition label — this number varies widely between brands.
Limitations: RER is an estimate, not a prescription. Individual metabolism varies, neutered/spayed pets often need 10–15% fewer calories, and some medical conditions significantly change energy needs. Treat this as a starting point and adjust over 4–8 weeks based on your pet's weight trend. Your vet is the best source for a precise feeding plan.
Frequently Asked Questions
The recommended daily amount depends on your dog's weight, age, and activity level. As a starting point, most adult dogs need between 25–30 kcal per pound of body weight per day. Our calculator uses the veterinary RER (Resting Energy Requirement) formula—70 × weight_kg^0.75—multiplied by an activity factor, then converts that to cups or grams based on your food's calorie density.
RER stands for Resting Energy Requirement—the calories a dog needs at rest to maintain basic body functions. Multiplying RER by an activity factor (1.0 for weight loss up to 1.6 for very active dogs) gives you a reliable daily calorie target. It's the same method veterinary nutritionists use as a starting point.
Select the 'Weight loss' activity level. This applies a multiplier of 1.0 to the RER, which is the baseline needed for weight loss in most dogs. Always confirm the target with your vet, who may adjust further based on body condition score.
Yes, significantly. A food with 350 kcal/cup and one with 500 kcal/cup both meet your dog's daily calorie target—but with very different cup amounts. Always check your food bag's calorie statement (usually listed per cup or per kilogram) and enter it for the most accurate result.
Most adult dogs do well with two meals per day. It reduces hunger between meals, may lower the risk of bloat in large breeds, and keeps energy levels stable. Our calculator splits the daily amount into two equal meals by default.