Cat Calorie Needs Calculator
Calculate your cat's daily calorie needs based on weight, age, activity level, and reproductive status for optimal feline nutrition.
Feeding a cat the right number of calories is one of the most important aspects of feline health care. Both overfeeding and underfeeding have serious consequences: obesity in cats is linked to diabetes, arthritis, and heart disease, while underfeeding causes muscle wasting and nutritional deficiencies.
The Feline Energy Requirement Formula
The World Small Animal Veterinary Association (WSAVA) and most veterinary nutrition guidelines use the following formula:
Resting Energy Requirement (RER) = 70 × (body weight in kg)^0.75
The RER is then multiplied by a life stage factor (also called the “illness factor” or “life factor”) to get the Daily Energy Requirement (DER):
DER = RER × Life Stage Factor
Life Stage Factors for Cats
| Status | Factor |
|---|---|
| Neutered adult, inactive | 1.2 |
| Neutered adult, typical activity | 1.4 |
| Intact adult, typical activity | 1.4 |
| Intact adult, active or outdoor | 1.6 |
| Overweight, weight loss goal | 0.8 × RER |
| Kitten under 4 months | 3.0 |
| Kitten 4–12 months | 2.5 |
| Pregnant cat | 1.6–2.0 |
| Nursing (lactating) cat | 2.0–6.0 (depends on litter size) |
Note what the weight-loss row multiplies. It is 0.8 × RER, the resting figure, not 0.8 × DER. Applying it to maintenance instead would leave a cat eating far too much to lose anything.
Example Calculation
A neutered 4 kg (8.8 lb) adult indoor cat:
- RER = 70 × (4)^0.75 = 70 × 2.83 = 198 kcal/day
- DER = 198 × 1.2 = 238 kcal/day
How Much Food Is That?
Calorie density varies significantly between food types:
- Dry kibble: typically 300–450 kcal per 100g. This calculator assumes 370, and a level 8 oz measuring cup holds roughly 100 g of kibble.
- Wet canned food: typically 90–120 kcal per 100g. This calculator assumes 112, which puts a 5.5 oz (156 g) can at about 175 kcal.
- Raw or home-cooked: varies widely, check individual recipes
Important Note
These are starting points. Individual cats vary in metabolism. Monitor your cat’s body condition score (BCS) monthly and adjust food amounts by 10% if the BCS is trending outside the ideal range. Always consult your veterinarian for personalized feeding advice, especially for overweight, senior, or health-compromised cats.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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