🔥 Pet Calorie Calculator
Find your pet's resting (RER) and daily (DER) calorie needs from its weight and life stage — the energy engine behind sensible portion sizes.
🔥 Calorie needs
RER = 70 × (weight kg)0.75 = 234 kcal; DER = RER × 1.6 (neutered adult) = 374 kcal/day. A general estimate — confirm with your exotic vet.
From calories to a real meal
Knowing the daily calorie target is the first step; the second is turning it into a portion. Once you have the DER here, the Pet Food Calculator converts it into grams of food using your diet's energy density and suggests how many meals to split it across.
Because RER uses metabolic body weight (weight to the power 0.75), a small animal needs proportionally more energy per kilogram than a large one — which is exactly why a flat per-kilo rule of thumb tends to over- or under-feed.
❓ Frequently Asked Questions
What is RER and how is it calculated?
RER is the Resting Energy Requirement — the calories an animal needs at rest to keep its body running. It is calculated as RER = 70 × (body weight in kilograms) raised to the power 0.75. This exponential (metabolic-weight) form scales better across body sizes than a simple per-kilogram figure.
What is DER, and which activity factor should I pick?
DER is the Daily Energy Requirement — RER multiplied by an activity or life-stage factor. Typical multipliers are 1.0 for weight loss, 1.6 for a neutered adult, 1.8 for an intact adult, 2.0 for active or working animals and older juveniles, and up to 3.0 for very young growing animals. Pick the one that best matches your pet's stage and lifestyle.
Can I use this for exotic species?
The RER/DER model originates in companion-animal nutrition and is a reasonable starting estimate for many mammals and birds, but metabolic rates vary widely across exotics — reptiles in particular have much lower energy needs. Use it as a guide, not a rule.
Should I rely on this instead of seeing a vet?
No — these are general estimates only. Calorie needs shift with health, breeding, temperature, and body condition, and exotic species vary enormously, so confirm targets with a qualified exotic or wildlife veterinarian.