# Kitten Feeding Calculator

How much to feed a kitten, by weight. Start from resting needs — 70 x (body weight in kg) raised to 0.75 — then multiply by 2.5, the growth factor the Merck Veterinary Manual publishes for kittens. Find the kcal per cup or per can on the label and divide the daily figure by it. Treats count toward the same total.

## Two sources, and they do not agree

Merck publishes one flat factor of 2.5 for the whole of kittenhood. FEDIAF (Nutritional Guidelines 2025, Table VII-10) publishes three steps instead:

| Age | x maintenance |
|---|---|
| Up to 4 months | 2–2.5 |
| 4 to 9 months | 1.75–2 |
| 9 to 12 months | 1.5 |

The two only overlap before 4 months, and only at the very top of FEDIAF's range. By one year Merck's figure sits 67% above what FEDIAF publishes. We calculate with Merck and show the gap rather than splitting the difference, because no document publishes a number in between. One reason not to average them: FEDIAF computes a cat's maintenance requirement on body weight to the power 0.67 (Heusner 1991) while Merck uses 0.75, and those exponents do not convert into one another.

## Common questions

### How much should I feed my kitten?

Start from resting needs — 70 × (body weight in kg) raised to 0.75 — then multiply by 2.5, the growth factor the Merck Veterinary Manual publishes for kittens. That gives calories a day. Look for the kcal per cup or per can on the label — every pet food sold in the United States must declare it — and divide the daily figure by that.

### Do other sources give the same answer?

No, and this is the clearest disagreement on the site. Merck publishes one flat factor of 2.5 for the whole of kittenhood. FEDIAF publishes three steps instead: 2–2.5 × up to four months, 1.75–2 × from four to nine months, and 1.5 × from nine to twelve. The two only overlap before four months, and only at the very top of FEDIAF's range. By one year Merck's figure is 67% above what FEDIAF publishes. We calculate with Merck and show you the gap rather than splitting the difference.

### Why can’t the two be averaged?

Because they aren't measuring from the same base. FEDIAF computes a cat's maintenance requirement on body weight to the power 0.67, citing the intra-specific coefficient proposed by Heusner in 1991; this calculator follows Merck, which uses 0.75. Those two exponents don't convert into one another, so averaging the multipliers would combine numbers that don't share a starting point.

### When does a kitten switch to adult food?

FEDIAF's table runs to twelve months, which is as far as it treats a cat as growing. What to switch to, and when, is a conversation with your veterinarian — the calorie figure here tells you how much, not which food.

### How much wet food should I feed a kitten?

The same daily calorie total applies whichever form the food takes; only the density changes. Wet food carries far fewer calories per gram than dry, so the same number of calories is a much larger volume. Find the kcal per can on the label and divide the daily figure by it — treats count toward the same total.

## Sources

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- Wikidata — cat breed mass (property P2067) — Wikimedia Foundation, query run 2026-07-28, CC0 license (https://query.wikidata.org/)
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- Dystocia in Small Animals — Merck Veterinary Manual, “Diagnosis of Dystocia in Small Animals” section, accessed 2026-07-28 (https://www.merckvetmanual.com/reproductive-system/reproductive-diseases-of-the-female-small-animal/dystocia-in-small-animals)
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- Chocolate Toxicosis in Animals — Merck Veterinary Manual, “Methylxanthine Content of Various Types of Chocolate” table and “Etiology” section, accessed 2026-07-28 (https://www.merckvetmanual.com/toxicology/food-hazards/chocolate-toxicosis-in-animals)
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- Calorie Needs for an Average Healthy Adult Cat in Ideal Body Condition — WSAVA Global Nutrition Committee, updated July 2020 (golden-test source, not used to build the calculation) (https://wsava.org/wp-content/uploads/2020/07/Calorie-Needs-for-Healthy-Adult-Cats-updated-July-2020.pdf)
- Assessment of body weight for age determination in kittens — DiGangi et al., Journal of Feline Medicine and Surgery, 2019 (tables 1 and 2, weight-for-age, male and female) (https://doi.org/10.1177/1098612X19844846)
- Kitten Age & Weight Chart — ASPCA Pro, 2023 (golden-test source, not used to build the calculation) (https://www.aspcapro.org/sites/default/files/2023-08/aspca_kittenchart_2023.pdf)

Full method: https://petmeasure.com/sources

_Verified 2026-07-28. Estimates only — this does not replace veterinary advice._