Key takeaways
- A neutered adult cat needs about 1.2 times its resting energy requirement, which is roughly 260 calories a day at 10 pounds.
- Intact adults need 1.4 times resting energy, obesity-prone cats 1.0 times, and healthy kittens 2.5 times, per the Merck Veterinary Manual.
- At a mid-tier dry food price, a 10-pound neutered cat costs about $12 a month to feed.
A neutered adult cat needs about 1.2 times its resting energy requirement each day. That is roughly 260 calories at 10 pounds. This cat calorie calculator guide shows the formula, a calories-by-weight table, kitten numbers, and the monthly food bill each calorie level produces.
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How many calories does a cat need? The RER formula
How many calories does a cat need starts with resting energy requirement, or RER. RER is 70 times body weight in kilograms, raised to the 0.75 power. It estimates the calories a resting cat burns in a day. A life-stage factor then raises or lowers the total.
A cat kcal calculator needs only three steps:
- Divide your cat's weight in pounds by 2.2 to get kilograms.
- Raise that number to the 0.75 power.
- Multiply by 70.
For a 10-pound cat, that gives 4.5 kilograms and an RER of about 218 calories. A real cat eats more than its resting number, so the next step multiplies it.
Cat daily energy factors by life stage
The Merck Veterinary Manual lists the factors in its daily maintenance energy requirement table. Multiply RER by the factor that fits your cat.
| Cat type | Factor | Calories for a 10-lb cat |
|---|---|---|
| Neutered adult | 1.2 x RER | about 261 |
| Intact adult | 1.4 x RER | about 305 |
| Obesity-prone adult | 1.0 x RER | about 218 |
| Healthy kitten | 2.5 x RER | based on kitten weight |
Every calculation is only a starting point, and the manual says it may need changing based on how the patient responds. Pregnant, nursing, and sick cats fall outside this table.
Cat calorie calculator: daily calories by weight
This cat calorie calculator table applies the adult factors to common weights. It also converts the neutered-adult number to cups and a monthly food cost. The example assumes a dry food with 400 calories per cup, priced at $2.50 a pound, with about 4 ounces per cup. Your own label will differ.
| Cat weight | RER | Neutered (1.2x) | Intact (1.4x) | Obesity-prone (1.0x) | Cups a day (neutered) | Monthly dry food cost |
|---|---|---|---|---|---|---|
| 6 lb | 149 | 178 | 208 | 149 | 0.45 | about $8 |
| 8 lb | 184 | 221 | 258 | 184 | 0.55 | about $10 |
| 10 lb | 218 | 261 | 305 | 218 | 0.65 | about $12 |
| 12 lb | 250 | 300 | 350 | 250 | 0.75 | about $14 |
| 14 lb | 280 | 337 | 393 | 280 | 0.84 | about $16 |
| 16 lb | 310 | 372 | 434 | 310 | 0.93 | about $17 |
| 18 lb | 339 | 406 | 474 | 339 | 1.02 | about $19 |
Find your cat's weight and read across for its life stage. A 12-pound intact cat needs about 350 calories. That is 50 more than a neutered cat of the same weight.
261 calories
The daily need of a neutered 10-pound adult cat, about 0.65 cups of a 400-calorie dry food and about $12 a month. See a food cost for your cat's breed in the PetBudget calculator.
How many calories should a kitten eat?
How many calories should a kitten eat depends on current weight, and the factor is 2.5 times RER. Kittens burn far more energy per pound than adults. Merck lists 2.5 times RER for healthy kittens and notes they can also be fed free choice.
| Kitten weight | RER | Daily calories (2.5x) |
|---|---|---|
| 1 lb | 39 | 97 |
| 2 lb | 65 | 163 |
| 3 lb | 88 | 221 |
| 4 lb | 110 | 274 |
| 6 lb | 149 | 371 |
A 4-pound kitten needs about 274 calories, more than a neutered 6-pound adult at 178. Recalculate every week or two, because the kitten gains weight quickly. Our kitten first-year cost guide shows the food bill for that year, which Great Pet Care puts at $351 to $584.
From calories to cups and cans
Calories end at the food label, because every food packs a different number into a cup or can. Look for "kcal per cup" on dry food and "kcal per can" on wet food. Divide your cat's daily calories by that number.
Two worked examples for a 10-pound neutered cat at 261 calories:
- Dry food at 400 kcal per cup. The cat needs 261 divided by 400, or about 0.65 cups.
- A wet food labeled 80 kcal per can. The cat needs about 3.3 cans.
For mixed feeding, split the calories. Give half from dry and half from wet, then convert each half separately. Our cat feeding guide covers wet and dry portions in more detail.
The Association for Pet Obesity Prevention advises owners to use a gram scale when possible, because a cup can vary widely. Treats should stay a small share of the day's calories.
Why the right calorie count matters
The right calorie count matters because most cats are overweight. In the Association for Pet Obesity Prevention's 2022 survey, 61% of cats were overweight or obese. The survey also found that 28% of owners called their cat's body condition normal when a veterinary professional scored it overweight or obese.
The same survey found that few cats lose weight when owners try on their own. Only 19% of owners who tried weight loss reported success. A measured calorie target is the simplest place to start, with your vet setting any weight-loss goal.
Check your cat's frame against our healthy cat weight chart. It shows typical weight ranges by size.
How to adjust the calorie target
Adjust the target by body condition, not by the table alone. Start at the calculated number, then reassess every few weeks. Change intake by small steps, about 10% at a time.
Use these checks:
- Feel the ribs. You should feel them under a thin layer of fat.
- Look from above. A healthy cat has a visible waist behind the ribs.
- Weigh monthly. Steady gain on a fixed diet means feeding less.
- Use a goal weight. For an overweight cat, calculate calories for the goal weight, with your vet.
Cats with kidney disease, diabetes, or other conditions need a vet-set target. Do not cut calories sharply on your own.
What cat calories cost over a year
Calories turn into a food bill at a steady rate. At $2.50 a pound, a neutered 10-pound cat costs about $12 a month, or about $147 a year, in dry food. A 16-pound cat costs about $17 a month, or about $209 a year.
PetBudget's model uses the same RER method with a 1.6 activity factor and 10% for treats. For a large breed such as the Maine Coon, that gives $325 a year for mid-tier dry food, per the Maine Coon cost breakdown. Wet and fresh foods cost more per calorie.
Food is one line in a cat's yearly total. Our guide to how much a cat costs shows first-year, annual, and lifetime numbers. For dogs, the dog calorie calculator applies the same method.
Put your cat's calories into a budget
Find your cat's weight in the table, read the daily calories, and convert them with your food's kcal per cup. Then multiply cups by 30 and by your price per cup for a monthly cost.
For a food cost tuned to your cat's breed and size, use the PetBudget calculator. The methodology page explains each input.
Frequently asked questions
How many calories does a cat need a day?
A neutered adult cat needs about 1.2 times its resting energy, which is 70 times body weight in kilograms to the 0.75 power. That works out to about 261 calories for a 10-pound cat. Treat it as a starting point and adjust by body condition.
How many calories should a kitten eat?
A healthy kitten needs about 2.5 times its resting energy, based on its current weight. A 2-pound kitten needs about 163 calories a day and a 4-pound kitten about 274. Kittens grow fast, so recalculate every week or two.
How do I calculate RER for a cat?
Divide the cat's weight in pounds by 2.2 to get kilograms. Raise that number to the 0.75 power, then multiply by 70. A 10-pound cat weighs 4.5 kilograms, so its RER is about 218 calories a day.
Do indoor cats need fewer calories?
Often yes. The Merck table uses 1.2 times RER for neutered adults and 1.0 times RER for obesity-prone cats. Many indoor cats fit the lower factor. Use body condition and weight trends, not the table alone.
How do I turn calories into cups or cans?
Divide your cat's daily calories by the kcal per cup or per can on the label. At 400 calories a cup, a 10-pound neutered cat needs about 0.65 cups. Always use your own food's number, since foods vary widely.
See your own pet's real numbers.
Run the calculator with your breed, metro area, and care choices for a first-year, annual, and lifetime cost estimate — not a national average.