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The current standard uses an allometric equation validated across body weights: RER = 70 × (body weight in kg)^0.75. This replaces the linear 30 × weight + 70 formula for animals over 2 kg.
RER (kcal/day) = 70 × Weight (kg)^0.75For animals between 2–45 kg, the simplified linear formula RER = 30 × weight(kg) + 70 provides similar results and is still widely used in clinical practice.
RER (kcal/day) = 30 × Weight (kg) + 70DER = RER × life-stage factor. Neutered adult dog: 1.6×. Active dog: 2.0–5.0×. Indoor cat: 1.2×. Kitten growth: 2.5×. These multipliers convert resting needs to actual feeding requirements.
DER = RER × Life-Stage FactorUpdated: July 2026
Typical indoor spayed female medium breed with normal activity.
→ RER ≈ 534 kcal/day; DER ≈ 854 kcal/day
Border collie with daily herding work and training sessions.
→ RER ≈ 897 kcal/day; DER ≈ 2,691 kcal/day
Neutered indoor cat with minimal activity and no outdoor access.
→ RER ≈ 218 kcal/day; DER ≈ 262 kcal/day
RER is resting metabolism only. Feeding RER to an active dog causes weight loss; feeding RER to a sedentary cat may still be too much if the multiplier is not applied correctly. Always multiply RER by the appropriate life-stage factor.
For weight loss plans, calculate RER based on ideal weight, not current weight. Using current weight of an obese pet overestimates caloric needs and slows weight loss progress.
Cats have lower activity multipliers (1.0–1.4× for most adults) compared to dogs (1.4–1.6× for neutered adults). Using dog factors for cats leads to overfeeding and obesity.
Resting Energy Requirement (RER) is the baseline caloric need for a healthy, resting animal at thermoneutral temperature. Veterinarians use RER as the foundation for calculating Daily Energy Requirement (DER) by applying life-stage and activity multipliers for feeding plans.