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When to switch to adult food

Puppy and kitten food is made for growth. You can switch once your pet is fully grown. When that is depends mostly on size.

The short answer

According to the Merck Veterinary Manual, small and medium dogs may be fully grown at 8–12 months, large and giant breeds often only at 10–16 months, some at almost 2 years. Kittens usually move to adult cat food between 8 and 12 months. On the growth curve in the FEDIAF guidelines, giant breeds weigh only about 82% of their adult weight at 12 months.

How far along is your dog?

The chart shows what percentage of its adult weight a dog typically reaches at 6, 9 and 12 months.

Adult weight6 months9 months12 months
Up to 15 lb77%92%100%
15–33 lb72%87%97%
33–61 lb69%85%97%
61–105 lb64%79%90%
Over 105 lb57%72%82%

Growth curves in the FEDIAF guidelines (2025), valid up to 1 year.

Dogs: what the sources say

  • Merck Veterinary Manual: small and medium dogs may be fully grown at 8–12 months, large and giant breeds often only at 10–16 months.
  • Tufts University: small dogs can move to adult food after 1 year; many large dogs like Labradors at 12 months too.
  • VCA: giant breeds can take up to 2 years to reach their adult weight and can stay on puppy food that long.

The American Kennel Club says small breeds can switch as early as 7 to 9 months. So the sources don’t fully agree. What’s certain: large dogs take longer.

Kittens: what the sources say

  • Merck Veterinary Manual: usually between 8 and 12 months.
  • Tufts University: after 1 year.
  • PDSA (UK animal charity): a kitten neutered at 4 months stays on kitten food until 6 months, then moves to a food for neutered cats.

When you switch

  • Switch slowly: mix old and new food over about a week.
  • Work out the amount again: with the new food’s calories and the dog or cat food calculator.
  • Keep weighing: an adult pet needs less energy per pound than a growing one.

Questions

When should a dog switch to adult food?

When it’s fully grown: small and medium dogs usually at 8–12 months, large and giant breeds often only at 10–16 months or later (Merck Veterinary Manual).

When should a cat switch to adult food?

Usually between 8 and 12 months (Merck Veterinary Manual). If your kitten is spayed or neutered early, a food for neutered cats may fit sooner. Ask your vet.

Is my dog fully grown at 12 months?

Small dogs usually are. On the growth curve, giant breeds weigh only about 82% of their adult weight at 12 months and keep growing.

Sources

Last checked: October 2026