How Much to Feed a Kitten: Kitten Feeding Calculator

By Marcos Ortega · Updated October 25, 2026 · Runs in your browser; nothing you type is sent anywhere.

Educational estimate, not veterinary advice. These numbers come from published averages and can be wrong for your pet. Your veterinarian, who can examine your dog or cat, is the right person to decide what is healthy for them.

Kittens need far more energy for their size than adult cats. This calculator applies the kitten factor from the Merck Veterinary Manual to your kitten’s weight today and converts the result to cups of your kitten food.

How the calculator works

RER (kcal/day) = 70 × (weight in kg)^0.75
Kitten: daily energy = 2.5 × RER

Merck lists 2.5 × RER for healthy kittens and adds that kittens can alternatively be fed free choice. Divide the daily calories by the calories per cup on the label for dry food, or by the calories per can or pouch for wet food.

For comparison, Merck gives 1.2 × RER for a neutered adult cat: a kitten needs about twice as many calories as an adult of the same weight.

Kitten feeding chart by weight

Kitten’s weight	RER (kcal)	Kitten, 2.5 × RER (kcal/day)	Cups/day at 450 kcal/cup
1 lb	39	97	0.21
2 lb	65	163	0.36
3 lb	88	220	0.49
4 lb	109	274	0.61
5 lb	129	323	0.72
6 lb	148	371	0.82
7 lb	167	416	0.93
8 lb	184	460	1.02

Rounded. 450 kcal per cup is an example; use the value on your bag.

How fast kittens grow

Merck gives a normal birth weight of 90–100 g (about 3–3.5 oz). Kittens gain 50–100 g a week for the first 3–4 months, growth slows at about 150–160 days, and it is usually complete by 200–220 days. Because the calories follow the weight, recalculate every week or two. Our kitten weight chart shows typical weights by age.

Worked examples

Example 1: a 4-month-old kitten weighing 4 lb, dry food with 450 kcal per cup. 4 lb = 1.81 kg. RER = 70 × 1.81^0.75 = 70 × 1.56 = 109 kcal. × 2.5 = 274 kcal per day ÷ 450 = 0.61 cups per day. Normal variation (±50%): 137–410 kcal.

Example 2: an 8-month-old kitten weighing 6 lb. RER = 148 kcal. × 2.5 = 371 kcal per day, or 0.82 cups of the same food.

Limitations

A single factor for the whole first year. Merck’s 2.5 × RER doesn’t change with age, while real needs fall as growth slows. Watch your kitten’s body condition as it nears adult size.
Large individual variation, up to 50% either way according to AAHA.
Health first. A kitten that isn’t gaining weight, or stops eating, needs a vet visit, not a new calculation.

Frequently asked questions

How often should I feed a kitten?

The Merck Veterinary Manual says growing kittens can be fed ad lib (food always available) or several times a day to meet their daily needs. It doesn't give a fixed number of meals; ask your vet what suits your kitten and household.

When do kittens stop growing?

Merck says kittens grow exceptionally fast for the first 3–4 months, growth begins to plateau at 150–160 days old, and is usually complete within 200–220 days (about 7 months).

When should my kitten switch to adult food?

Merck says kittens are generally moved to an adult diet sometime between 8 and 12 months. Your vet can tell you when for your kitten.

My kitten eats wet food. Can I use this?

Yes. Use the calories per day and divide by the kcal per can or pouch printed on the label. The cups line only applies to dry food.

How accurate is it?

AAHA's nutrition guidelines say individual cats' energy needs can vary by 50% in either direction from calculated values, so treat the result as a starting point and watch your kitten's weight and body condition.

Sources

Merck Veterinary Manual. Nutritional Requirements of Small Animals. Checked October 25, 2026.

Merck Veterinary Manual (Sanderson SL). Feeding Practices in Small Animals. Checked October 25, 2026.

American Animal Hospital Association (AAHA). AAHA Nutritional Assessment Guidelines for Dogs and Cats (2010). Checked October 25, 2026.