How does a kitten grow, breed by breed? The answer depends on its size: most cats finish growing at about 12 months, but large breeds such as the Maine Coon can keep growing until they are 2 to 4 years old. This guide is the kitten growth chart by breed: eight breeds with their size, adult weight, and the age at which they are usually fully grown — and how to judge your own kitten's growth. Every figure is a typical range, not a promise: individual cats vary. The kitten weight predictor estimates adult weight from a kitten's current weight and age.
The short version is: most kittens finish growing at about 12 months, large breeds take longer, and a kitten is fully grown when it has reached its adult height and weight — which is not the same as being an adult. A kitten that has stopped growing still needs training, socialisation, and care, and it should not be switched to adult food until it has finished growing. The when is a cat fully grown guide gives the growth ages by size, and the kitten weight chart by age guide gives the growth shares by age.
Kitten growth chart by breed
The table below lists eight breeds with their size, typical adult weight, and the age at which they are usually fully grown. Use it to see where your breed sits — and to know when to expect your kitten to stop growing.
| Breed | Size | Typical adult weight | Fully grown at |
|---|---|---|---|
| Persian | Medium | 3–6 kg | About 12 months |
| Maine Coon | Large | 6–11 kg | 12 months–2 years (Maine Coon up to 4 years) |
| Siamese | Medium | 3–5 kg | About 12 months |
| Bengal | Medium | 4–7 kg | About 12 months |
| Ragdoll | Large | 5–9 kg | 12 months–2 years (Maine Coon up to 4 years) |
| British Shorthair | Medium | 4–8 kg | About 12 months |
| Russian Blue | Medium | 3–5 kg | About 12 months |
| Singapura | Small | 2–3 kg | About 12 months |
Read the table from top to bottom and the pattern is clear: the smaller the breed, the sooner it finishes growing. A Singapura is usually fully grown at about 12 months, while a Maine Coon can keep growing until it is 2 to 4 years old. The cat breeds hub lists every cat breed on this site by size and group.
How a kitten grows
A kitten grows fastest in its first few months: it is about a fifth to a quarter of its adult weight at 8 weeks, about half at 6 months, and about four-fifths or more at 12 months, when most breeds are near-adult and large breeds are still growing. A kitten that is a large breed will grow for longer than one that is a small breed, and a kitten with a heavy frame will fill out for longer than one with a light frame.
A kitten that is a crossbreed will grow at a pace between its parents' breeds, and its adult weight will be between theirs — so a crossbreed's growth is harder to predict, and the ranges on this site are typical estimates, not guarantees for any one cat. To judge your own kitten's growth, weigh it every two weeks as a young animal, and write the result down: a single reading matters less than the line over weeks. The kitten weight chart by age guide gives the growth shares by age.
When to switch from kitten to adult food
Switch from kitten to adult food when your cat has finished growing: at about 12 months for most breeds, or later for a large breed such as the Maine Coon. Switch gradually, over a week: mix the new food with the old, increasing the new food a little each day, so the stomach has time to adjust.
Do not switch too early: a kitten that is switched to adult food before it has finished growing may not get the nutrients it needs, and it may grow more slowly or less well. Do not switch too late, either: an adult cat that is still eating kitten food will get too many calories, and it may gain weight. The kitten feeding schedule by age guide gives the feeding schedule from weaning to adulthood, and the cat food calculator works out the daily calories for any weight and stage.
Growth problems to watch for
A kitten that grows too fast can develop joint problems, and a kitten that grows too slowly may have a health problem, or it may not be getting enough food. A kitten that is not gaining weight at all over two weeks, or that is losing weight, needs a vet check. A kitten that is limping, stiff, or in pain needs a vet check, too: joint problems in a growing kitten can be treated, but they need to be found early.
A vet can work out whether the growth is normal, and what to do about it. The how much food should a kitten eat guide gives the calorie tables for kittens, and the kitten age calculator by weeks guide gives the development at each age.
How to track your kitten's growth
Weigh your kitten every two weeks, and write the result down: a kitten that is gaining weight steadily is growing well, and a kitten that is not gaining weight at all over two weeks, or that is losing weight, needs a vet check. The line over weeks matters more than any single reading. Use the kitten weight predictor to estimate adult weight from the kitten's current weight and age, and compare the result to the typical adult weight for the breed in the table above.
Remember that the table gives typical ranges, not promises: a cat that is a little above or below the range for its breed is usually fine, as long as it is gaining weight steadily and is bright, eating, and active. What matters is the line over weeks: a smooth, steady rise, not a flat line and not a sudden jump. The cat age calculator works out the human-age equivalent for any age.
For related reading, see the kitten weight predictor, the when is a cat fully grown guide, the kitten weight chart by age guide, the kitten feeding schedule by age guide, the cat growth chart by breed guide, the cat breeds hub.
Frequently asked questions
How does a kitten grow, breed by breed?
It depends on its size: most cats finish growing at about 12 months, but large breeds such as the Maine Coon can keep growing until they are 2 to 4 years old. The table above gives eight breeds with their size, adult weight, and the age at which they are usually fully grown.
When is a cat fully grown?
Most cats are usually fully grown at about 12 months, but large breeds such as the Maine Coon can keep growing until they are 2 to 4 years old. Those are guides, not hard lines.
When should I switch from kitten food to adult food?
Switch when your cat has finished growing: at about 12 months for most breeds, or later for a large breed such as the Maine Coon. Switch gradually, over a week: mix the new food with the old, increasing the new food a little each day.
How fast does a kitten grow?
A kitten grows fastest in its first few months: it is about a fifth to a quarter of its adult weight at 8 weeks, about half at 6 months, and about four-fifths or more at 12 months, when most breeds are near-adult and large breeds are still growing. Weigh it every two weeks, and write the result down.
How do I know if my kitten is growing well?
Weigh it every two weeks and write the result down: a kitten that is gaining weight steadily is growing well. A kitten that is not gaining weight at all over two weeks, or that is losing weight, needs a vet check. The line over weeks matters more than any single reading.
When should I ask a vet about growth?
Ask a vet if your kitten is not gaining weight at all over two weeks, if it is losing weight, if it is growing much faster or much slower than expected for its breed, or if it is limping, stiff, or in pain.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.