Pets
Cat Calorie Calculator
Enter your cat's weight, life stage, activity level, and whether they live indoors or outdoors. We compute the Resting Energy Requirement and the Daily Energy Requirement using the standard veterinary formulas.
Life stage
Activity level
Lifestyle
Daily Energy Requirement
261 kcal
1.2× RER · 4.54 kg
Estimate only. Cats trend toward chronic over-feeding when owners go by the bag's instructions — body condition is the better gauge.
Examples
10 lb adult, indoor, normal activity
RER ≈ 218 · DER ≈ 261 kcal
8 lb adult, indoor, low activity
RER ≈ 184 · DER ≈ 184 kcal
4 lb kitten under 4 months
RER ≈ 109 · DER ≈ 274 kcal
12 lb adult, outdoor, high activity
RER ≈ 249 · DER ≈ 399 kcal
How it works
We use the standard veterinary RER formula and a multiplier tuned to life stage and lifestyle. The result is the starting calorie target for an average healthy cat at your inputs.
RER · 70 × (body weight in kg)^0.75
DER · RER × multiplier
Multipliers used: kitten <4mo 2.5 · kitten 4–12mo 2.0 · adult indoor low/normal/high 1.0/1.2/1.4 · adult outdoor +0.2 · senior 1.0
Estimate, not advice. This is a calculator, not veterinary guidance. Use the result as a starting point and confirm with your vet — body condition, breed, and individual health matter more than any formula.
Frequently asked questions
RER (Resting Energy Requirement) is the calories a cat burns at rest — the metabolic baseline. DER (Daily Energy Requirement) is RER multiplied by an activity factor reflecting life stage and lifestyle. DER is the figure you actually feed.
Outdoor cats — and indoor cats with very active play routines — burn more calories than mostly-sedentary indoor cats. The standard veterinary multipliers reflect this: a typical indoor adult cat needs about 1.0–1.2× RER, while an active outdoor cat may need 1.4–1.6× RER. Most pet cats fall in the indoor range.
RER (70 × kg^0.75) and the standard multipliers come from veterinary nutrition guidelines and are widely used in clinic feeding plans. They produce reasonable starting points for most healthy cats. Individual variation can be ±20% — adjust based on body condition and your vet's recommendation.
Many indoor pet cats are on the sedentary end of "low activity." If your cat sleeps 16+ hours a day and rarely runs around, lean toward 1.0× RER (or even 0.8× if a vet has prescribed weight loss). The number on the bag of food is usually generous — most calorie-related health issues in cats come from chronic over-feeding.
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