Your cat's name (optional, makes results personal)

Weight

Life Stage

Spayed / Neutered

Activity Level

✓ Vet-standard RER/MER formula

✓ Works with any brand of food

✓ Free forever, no sign-up

calories per day

🔥 Resting Energy (RER)

⚡ Daily Energy (MER)

🐟 Meals Per Day

🍽️ Per Meal

Now that you know the calories, find out exactly how much food to put in the bowl.

How much should I feed my cat? →

How This Calculator Works

This calculator uses the Resting Energy Requirement (RER) and Maintenance Energy Requirement (MER) equations, the same approach used by veterinary nutritionists to estimate calorie needs in cats.

Your cat's resting energy needs are calculated with RER = 70 × (body weight in kg)^0.75, then multiplied by a factor based on age, activity, and spay/neuter status. The result is an estimate of how many calories your cat needs per day to maintain a healthy weight.

Daily Calorie Needs by Cat Size

Here's a quick reference for typical neutered adult cats at moderate activity:

Cat Size	Weight	Daily Calories	Notes
Small	6 lbs	~180 kcal	Siamese, Singapura
Average	10 lbs	~260 kcal	Most domestic cats
Large	14 lbs	~335 kcal	Maine Coon, Ragdoll
Very Large	18 lbs	~405 kcal	Large Maine Coon

Understanding Cat Calorie Needs

Cats are obligate carnivores with unique metabolic needs compared to dogs. They require a higher percentage of calories from protein and have less metabolic flexibility. However, the same RER/MER approach applies for estimating total calorie needs.

Indoor vs. Outdoor Cats

Indoor-only cats are significantly more sedentary than outdoor or indoor-outdoor cats. An indoor cat who mainly sleeps and lounges should be classified as "sedentary," which many cat owners find surprising. Overfeeding indoor cats is one of the leading causes of feline overweight and obesity, which affects an estimated 60% of domestic cats.

Spayed/Neutered Cats

Like dogs, spayed and neutered cats experience a metabolic shift that reduces energy needs by roughly 15%. Most cats are spayed or neutered, so this is the default in our calculator. If your cat is intact, toggle this off for a more accurate estimate.

Senior and Geriatric Cats

Cats over 11 are considered senior, and those over 15 are geriatric. Senior cats often need fewer calories due to reduced activity, but geriatric cats can paradoxically need more calories because their ability to digest and absorb nutrients declines. Our calculator accounts for this with separate factors for senior (11 to 14) and geriatric (15+) cats.

Wet Food vs. Dry Food

Wet food typically has 70 to 100 calories per 3-oz can, while dry food has 300 to 500 calories per cup. Many veterinarians recommend wet food for cats because it provides additional hydration. Cats evolved to get most of their water from food. The calorie needs are the same regardless of food type; only the volume changes.

Frequently Asked Questions

A typical 10-pound neutered indoor adult cat needs about 200 to 280 calories per day. Kittens need more per pound of body weight, while sedentary senior cats may need as few as 170 calories. Use the calculator above for a personalized estimate.

Your cat's calorie needs stay the same. Only the volume of food changes. Wet food has about 70 to 100 calories per 3-oz can, while dry has 300 to 500 per cup. A cat eating 250 calories per day might need about 2/3 cup of dry food or 2.5 to 3 cans of wet food. Use the feeding calculator above to get exact amounts.

Don't cut calories drastically without veterinary guidance. Cats can develop a serious condition called hepatic lipidosis (fatty liver disease) if they lose weight too quickly. A safe rate is about 1 to 2% of body weight per week. Talk to your vet about a gradual weight loss plan.

Cats over 15 often experience reduced digestive efficiency, absorbing fewer nutrients from the same amount of food. Research shows that geriatric cats may need 25 to 50% more calories than middle-aged adults to maintain body weight, even though they're less active.

We use the standard veterinary formula: RER = 70 × (body weight in kg)^0.75, then multiply by life stage and activity factors to get the Maintenance Energy Requirement (MER). This is the same formula used by veterinary nutritionists and the Merck Veterinary Manual.

Last reviewed: April 1, 2026