Kitten Food Calculator

Quick answer. A 1.5 kg kitten needs about 237 kcal a day (RER 95 × 2.5), fed in three to four small meals. Kittens use more energy per kilogram to grow, so the factor stays at 2.5 until around 12 months. Weigh your kitten regularly and ask your vet if weight gain stalls.

How to use the kitten food calculator

Enter your kitten's weight.
Enter the age in weeks.
Optional: enter the kcal/kg of the kitten food to also see grams per day.
Press Calculate.

Worked example

A 10-week-old kitten weighing 1.5 kg, eating a kitten food that lists 4,000 kcal/kg.

Kitten's weight: 1.5 kg
Age (weeks): 10
Food kcal/kg: 4000

237 kcal/day

Energy need: 237 kcal/day
Food per day: 59 g (2.1 oz)
Meals per day: 3–4

Example values are illustrative; this result is produced by the same calculator above.

How we calculate it

RER (kcal/day) = 70 × BW(kg)^0.75; MER = RER × 2.5 until ~12 months; split into 3–4 meals

Sources: NRC · Merck Veterinary Manual

Reference table

Kitten energy need (2.5 × RER)
Weight	kcal/day
0.5 kg	104
1 kg	175
1.5 kg	237
2 kg	294
3 kg	399
4 kg	495

Understanding your result

Kittens grow fast and need more energy per kilogram than adult cats. The calculator uses the resting energy formula (70 × weight in kg to the power 0.75) and multiplies it by 2.5 for a kitten, then converts the result to grams of your food using its kcal per kg.

Very young kittens eat many small meals, so the tool also suggests how many meals to divide the daily amount into, based on age in weeks.

Because kittens gain weight quickly, repeat the calculation every week or two with a fresh weight.

Common mistakes

Using an adult cat food value. Kitten food is more energy dense.
Entering the kitten's age in months where the tool expects weeks.
Feeding by the packet alone without weighing the kitten.
Leaving food out all day, which makes it hard to know how much is eaten.

Good to know

Kittens under four weeks old, orphaned kittens and sick kittens need veterinary guidance.
No weight gain for several days is a reason to call your vet.
Move to adult food only when your vet or the food label says the kitten is ready.

When to talk to your vet

Kittens under 4 weeks or orphaned kittens
No weight gain for several days
Diarrhoea, vomiting or lethargy

Frequently asked questions

How much should a kitten eat?

Kittens need about 2.5 × RER until around 12 months. A 1.5 kg kitten needs about 237 kcal a day.

How much wet food should a kitten eat?

Divide the calories by the wet food's kcal per kg; wet food amounts look large because of the water content.

How often should kittens eat?

Three to four small meals a day until about 6 months, then two to three.

When do kittens switch to adult food?

Around 12 months for most cats; large breeds such as Maine Coons may stay on kitten food longer — ask your vet.

Is this for orphaned or very young kittens?

No. Kittens under 4 weeks or orphaned kittens need veterinary guidance. Call your vet if there is no weight gain for several days.

Why is the kitten factor 2.5?

Kittens use more energy per kilogram to grow, so maintenance energy is estimated as 2.5 × RER until around 12 months, compared with 1.2 for a neutered adult cat.

Reviewed by a licensed veterinarian

Last reviewed 18 Oct 2026 · How we review

Sources

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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.