How to use the cat food calculator
- Enter your cat's weight.
- Choose the life stage.
- Set how much of the diet comes from wet food.
- Enter the kcal/kg of each food and press Calculate.
Worked example
Milo, a neutered adult cat weighing 4 kg, fed half wet food (1,000 kcal/kg) and half dry food (3,800 kcal/kg).
- Cat's current weight
- 4 kg
- Life stage
- Neutered/spayed adult
- % of calories from wet food
- 50%
- Wet food kcal/kg
- 1000
- Dry food kcal/kg
- 3800
- Energy need
- 238 kcal/day
- Wet food per day
- 120 g
- Dry food per day
- 31 g
Example values are illustrative; this result is produced by the same calculator above.
How we calculate it
Sources: NRC · WSAVA Global Nutrition Guidelines · Merck Veterinary Manual
Reference table
| Weight | kcal/day |
|---|---|
| 2 kg / 4 lb | 141 |
| 3 kg / 7 lb | 191 |
| 4 kg / 9 lb | 238 |
| 5 kg / 11 lb | 281 |
| 6 kg / 13 lb | 322 |
| 7 kg / 15 lb | 361 |
Understanding your result
The tool estimates your cat's resting energy requirement (RER) with 70 × body weight in kg to the power 0.75, then applies a cat factor: 1.2 for a neutered adult, 1.4 for an intact adult or 1.0 for an inactive cat that gains weight easily. The result is the daily energy target in kcal.
Cats are often fed a mix of wet and dry food, which have very different energy densities. The wet-food slider sets what share of calories comes from wet food, and the calculator converts each share into grams using the kcal per kg of each product.
Use the grams as a daily total and split them into the number of meals that suits your routine. If your cat's weight drifts up or down over a few weeks, adjust the portion by a small amount and recheck.
Common mistakes
- Entering the kcal per tin or pouch instead of kcal per kg. Check which unit the label uses.
- Forgetting that wet food is mostly water, so the grams look large while the calories are modest.
- Counting only meals and ignoring treats and licks of other food.
- Using the target weight of an overweight cat; use the current weight and ask your vet about a weight-loss plan.
Good to know
- Kittens, pregnant or nursing cats and cats with medical problems have different needs; use the kitten calculator or ask your vet.
- A cat that stops eating for more than a day needs a vet visit, not a smaller portion.
- Body condition matters more than the number on the scale. You should be able to feel the ribs under a thin layer of fat.
When to talk to your vet
- Your cat stops eating for more than 24 hours
- Sudden weight loss or gain
- Your cat is pregnant, nursing or has a medical condition
Frequently asked questions
How much should I feed my cat?
A 4 kg neutered indoor cat needs about 238 kcal a day. Convert that into grams using the energy on your cat food label.
How much wet food should a cat eat?
Wet foods are mostly water (around 75–80%), so the grams are much higher than dry food for the same calories. Use the wet share slider to see both.
How many grams of dry food for a cat?
Divide the calories by the dry food's kcal per kg and multiply by 1,000. Many dry foods give 50–70 g for an average adult cat.
How often should I feed my cat?
Two or more small meals a day suits most cats; puzzle feeders help indoor cats stay active.
Can I use this for weight loss?
Cats must lose weight slowly. Talk to your vet before cutting calories — crash diets can cause serious liver disease in cats.
Is this the right calculator for kittens or pregnant cats?
No. Kittens, pregnant and nursing cats need more energy, and cats with medical conditions need a vet's plan. Use the Kitten Food Calculator for growing kittens and ask your vet about the others.
Why is the factor 1.2 for a neutered cat?
Maintenance energy is estimated as resting energy (RER) multiplied by a life-stage factor: 1.2 for a neutered adult cat, 1.4 for an intact adult and 1.0 for an inactive or obesity-prone cat. The result is a starting point to adjust by body condition.
Sources
- NRC (2006) Nutrient Requirements of Dogs and Cats, National Academies Press
- WSAVA Global Nutrition Guidelines (incl. 9-point BCS charts)
- Merck Veterinary Manual — Nutritional Requirements of Small Animals (incl. maintenance energy table)
Related calculators
- Kitten Food CalculatorFind out how many calories a growing kitten needs and how much food that is.
- Cat Age CalculatorConvert your cat's age into human years and see its life stage.
- Cat Pregnancy Due Date CalculatorEstimate when your cat's kittens are due.
- Cat Calorie CalculatorWork out how many calories your cat needs each day, from its weight and life stage.
Estimates only. Every pet is different — confirm with your veterinarian. If your pet may have eaten something harmful, contact your vet or an animal poison helpline now.