Last updated: May 11, 2026

Cat Calorie Calculator

Estimate daily calories for a cat from weight, life stage, neuter status, and activity level.

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Alpha Calculators Team

Created by Alpha Calculators Team

Editorial Team

Cat Calorie Calculator

Enter your values and the calculator will update automatically.

Results

Estimated daily calories
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Resting energy (RER)
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Calories per meal
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Max treat calories (10%)
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Daily food portions
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How this was calculated
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A cat calorie calculator estimates daily calories by applying a veterinary RER formula to body weight, then adjusting for life stage, neuter status, body condition, activity level, and weight goal. Enter your cat's details above to get an estimated daily calorie target, calories per meal, and a safe treat limit.
Cat with a measured food bowl and kitchen scale for estimating daily calories
A measured feeding setup makes calorie estimates easier to apply consistently.
Cat body condition guide for estimating healthy weight and calorie needs
Body condition helps adjust calorie targets beyond weight alone. Use visible waist, rib feel, and belly shape as a guide, and confirm concerns with your veterinarian.

Cat calorie formula

The calculator computes RER from metabolic body weight, then multiplies by a coefficient that combines life stage, neuter status, activity, and body condition. Selecting lose weight or gain weight overrides the combined coefficient with a standard veterinary factor.
RER = 70 × weightKg^0.75
MER (maintain) = RER × age × neuter × activity × body condition
MER (lose weight) = RER × 0.8
MER (gain weight) = RER × 1.8

Factors used by the calculator

The combined coefficient for the maintain goal is a product of all applicable factors. A lose or gain goal overrides the combined coefficient entirely.
Factor Option Value
Age stage Adult 1.0
Age stage Senior or lower metabolism 0.95
Age stage Kitten 4 to 12 months 2.0
Age stage Kitten under 4 months 2.5
Neuter status Neutered or spayed 1.2
Neuter status Intact adult 1.4
Activity Less active or obesity-prone 0.8
Activity Typical indoor cat 1.0
Activity Active indoor or outdoor access 1.2
Body condition Underweight 1.1
Body condition Ideal weight 1.0
Body condition Overweight 0.9
Body condition Obese 0.85
Goal Lose weight 0.8 × RER (overrides all factors)
Goal Gain weight 1.8 × RER (overrides all factors)

What RER and MER mean

RER is the resting energy requirement, the estimated calories a cat needs for basic body functions at rest. It is calculated from metabolic body weight using the formula 70 × weightKg^0.75. This formula scales more accurately across different body sizes than a simple calories-per-pound rule.

MER is the maintenance energy requirement. It adjusts RER for real-world factors including life stage, neuter status, activity level, and body condition. Most adult neutered indoor cats have an MER between 1.0 and 1.4 times their RER. Kittens and highly active cats need significantly more.

These are commonly used veterinary estimating factors, not universal standards. The Ohio State University Veterinary Medical Center notes that individual needs can vary by roughly 50 percent from calculated values, so adjust the feeding amount based on your cat's actual weight changes over time.

How many calories should a cat eat by weight?

Estimates below are for an adult neutered cat at ideal body weight with typical indoor activity (coefficient 1.2). Use the calculator above for a personalized estimate.
Weight (lb) Weight (kg) RER (kcal/day) Estimated daily calories
5 lb 2.3 kg 131 157
8 lb 3.6 kg 183 220
10 lb 4.5 kg 216 259
12 lb 5.4 kg 248 298
15 lb 6.8 kg 295 354

How many treat calories can my cat have?

The calculator shows the 10 percent treat limit as the max treat calories result. For a cat needing 250 kcal/day, that is about 25 kcal from treats.

When giving treats, count them within the daily total rather than adding them on top. Most commercial cat treats list calorie content on the label or the manufacturer website. High-treat diets can push cats into a calorie surplus unnoticed, especially less-active indoor cats.

Current weight or ideal weight?

For a cat at a healthy body condition, use current weight. For a cat that needs to lose weight, veterinarians typically calculate the calorie target using the cat's target or ideal weight rather than current weight. If your vet has given you a goal weight, enter that value in the calculator with the lose weight goal selected.

How to convert calories into cups or cans

Once you know your cat's daily calorie need, divide by the calorie density of your food to estimate the daily portion. For example, if your cat needs 230 kcal/day from food (after subtracting 10 percent for treats) and your dry food has 380 kcal per cup, the daily amount is roughly 230 ÷ 380 ≈ 0.6 cups per day.

The optional food calorie density field in the calculator above does this automatically. Enter the kcal per cup or kcal per can from your food label, and the daily food portions result will update.

Calorie density varies widely between brands and formats. Wet food typically ranges from 20 to 40 kcal per ounce; dry food typically ranges from 300 to 500 kcal per cup.

How to use the cat calorie calculator

  1. 1

    Weigh your cat or use a recent veterinary weight. For a weight loss plan, ask your vet for a target weight and enter that value.

  2. 2

    Select the closest age stage. Adult covers most cats from 1 to 7 years. Use Senior for older or lower-metabolism cats.

  3. 3

    Select neuter status and body condition. Body condition adjusts the coefficient slightly for maintain goal. Lose or gain goal overrides the full coefficient.

  4. 4

    Choose activity level. Typical indoor is the most common starting point. Adjust down for very sedentary cats or up for cats with regular outdoor access.

  5. 5

    Set meals per day to see the calorie split per meal. Optionally enter your food's kcal per cup or can to get an estimated daily food portion.

  6. 6

    Use the estimated daily calories as a starting point. Recheck body condition and weight every 4 to 6 weeks and adjust the feeding amount with your veterinarian's guidance.

When to adjust the estimate with veterinary guidance

The calculator gives a useful starting point, but some cats need a personalized calorie target.
  • Weight loss or weight gain programs, especially for obese cats.
  • Kittens, pregnancy, or nursing mothers.
  • Diabetes, kidney disease, hyperthyroidism, inflammatory bowel disease, or other chronic conditions.
  • Any cat whose weight or body condition has changed unexpectedly.
  • Cats on prescription or therapeutic diets with specific feeding instructions.

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Sources & References 4
  1. website, 2024
  2. website, 2024
  3. website, 2024
  4. website, 2024

Frequently Asked Questions

How many calories should my cat eat per day?
A typical adult neutered indoor cat needs roughly 1.2 times the resting energy requirement (RER). For a 10 lb neutered indoor cat, that is about 259 kcal per day. Use the calculator above for an estimate based on your cat's specific weight, age stage, body condition, and activity level.
How many calories should a 10 lb cat eat?
A 10 lb cat has an RER of approximately 216 kcal/day. For an adult neutered indoor cat at ideal weight, the estimated daily need is around 259 kcal/day. Active or intact cats need more; less-active or overweight cats need less.
How do I calculate my cat's RER?
RER stands for resting energy requirement. The veterinary formula is RER = 70 × body weight in kg to the power of 0.75. For a 4.5 kg cat, RER = 70 × 4.5^0.75 ≈ 216 kcal/day. The calculator does this automatically when you enter your cat's weight.
What is MER for cats?
MER stands for maintenance energy requirement. It adjusts RER for real-world factors such as life stage, neuter status, activity level, and body condition. Most adult neutered indoor cats have an MER between 1.0 and 1.4 times their RER.
Should I use current weight or ideal weight?
For maintenance, use your cat's current weight. For weight loss, your veterinarian may provide a target or ideal weight, which is more appropriate to use as the input. If your cat is obese, using current weight with the lose weight goal selected will give a conservative calorie target.
How many calories should a cat eat to lose weight?
The standard veterinary estimate for weight loss is 0.8 times RER, calculated using the cat's ideal or target weight. Sudden or aggressive calorie restriction is dangerous for cats. Work with your veterinarian to set a safe rate of loss.
How much of my cat's calories can come from treats?
Treats should generally stay under 10 percent of total daily calories. If your cat needs 250 kcal/day, treats should be no more than about 25 kcal/day. The calculator shows this as the max treat calories result.
Is this safe for overweight or obese cats?
This calculator provides a starting estimate only. For overweight or obese cats, work with a veterinarian before starting any weight loss program. Cats are at risk of hepatic lipidosis if calorie restriction is too rapid or if they stop eating.

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