This free calculator estimates your dog's resting energy requirement (RER) from body weight, scales it by life stage to get daily energy requirement (DER), and converts the result into cups of the food you actually feed. Enter weight, life stage, activity level, and your food's kcal per cup to get a daily calorie target and a measured portion. It is free, with no account needed, and the method is based on the Merck Veterinary Manual and WSAVA Global Nutrition Guidelines.