How much should a kitten weigh by age? The honest answer is: it depends on the breed and its size, and on the kitten's age — a kitten's weight is a moving target, because a kitten is growing fast. A small breed kitten may be an adult at 2 to 3 kg, while a large breed kitten may grow to 6 to 11 kg, and the two kittens follow very different growth curves to get there. This guide is the kitten weight chart by age in words: the growth milestones by age, the expected adult weight by size and by breed, how to weigh a kitten and track its growth, and when a kitten's weight is a reason to call the vet.
The kitten months are when weight habits are set for life, and they are also when weight mistakes are easiest to make, because the right weight changes so fast. A kitten that is overfed grows up overweight, and a kitten that is underfed grows up stunted. Both problems are much harder to fix in adulthood than to prevent in kittenhood. Weigh the kitten every two weeks, compare with the breed's expected adult weight, and use the tables below as a starting point, then adjust by body condition: you should be able to feel the ribs easily under a thin layer of fat and see a waist from above and from the side, even in a kitten.
Kitten growth milestones by age
A kitten's first year is a series of short stages, and each one has its own needs. From birth to about 8 weeks, a kitten is with its mother and littermates, learning the basics of being a cat — how to play without hurting, how to use a litter tray, and how to read other cats. From 8 weeks to about 16 weeks is the socialisation window, the most important few weeks of the cat's life: the kitten should meet many different people, places, sounds, and surfaces, gently and positively, because the attitudes formed in this window last for life. A kitten that misses socialisation in this window is much harder to socialise later, and may stay fearful of strangers or of new places for life.
| Kitten age | Milestone |
|---|---|
| Birth | Eyes closed, nursing, fully dependent on its mother |
| 2 weeks | Eyes open, starting to move around |
| 4 weeks | Weaning begins, first tastes of solid food |
| 8 weeks | Eating solid food, ready for a new home, first vaccinations |
| 3 months | Rapid growth, intense play, socialisation window |
| 6 months | About half to two-thirds of expected adult weight, as a rough guide |
| 9 months | Most of adult size for small and medium breeds, still growing for large breeds |
| 12 months | Near adult weight for small and medium breeds; large breeds still growing |
The milestones in the table are rough guides, not fixed dates: individual kittens vary, and large breeds move through them more slowly than small breeds. The weight figures in the table are given as a rough share of expected adult weight, not in grams, because a kitten's weight in grams depends entirely on its breed and its expected adult weight — a Maine Coon kitten at 6 months weighs far more than a Singapura kitten at the same age, and both can be growing perfectly well. Use the adult weight ranges in the next section with the rough shares here, and ask your vet to check growth if your kitten is well outside them. The kitten cat weight calculator guide gives the same numbers by breed size, and the kitten age in human years guide explains the life stages the growth follows.
Expected adult weight by breed size
The expected adult weight for a kitten follows its breed size, and the size bands are the starting point for any kitten weight estimate. Small breeds, at 2 to 4 kg as adults, typically weigh 2 to 4 kg and live 12 to 16 years. Medium breeds, at 3 to 6 kg, typically weigh 3 to 6 kg and live 12 to 16 years. Large breeds, at 5 to 11 kg, typically weigh 5 to 11 kg and live 10 to 14 years. Those ranges are the typical ranges for cats of each size — an estimate where no published breed-standard range was available, not a breed-specific measurement.
| Size | Typical adult weight | Typical lifespan |
|---|---|---|
| Small (2–4 kg) | 2–4 kg | 12–16 years |
| Medium (3–6 kg) | 3–6 kg | 12–16 years |
| Large (5–11 kg) | 5–11 kg | 10–14 years |
Breed ranges are a better guide than size ranges where they exist, because they narrow the band. A Maine Coon is typically 6 to 11 kg as an adult, a Ragdoll 5 to 9 kg, a British Shorthair 4 to 8 kg, a Siamese 3 to 5 kg, a Bengal 4 to 7 kg, a Singapura 2 to 3 kg, and a Munchkin 2 to 4 kg. If you know your kitten's breed, use the breed range first and the size range second. The large breeds also take longer to finish growing: a Maine Coon can take 2 to 4 years to finish growing, and a Ragdoll up to 4 years, while a small or medium breed is usually an adult by about 12 months. The kitten weight predictor estimates adult weight from the kitten's current weight and age, and the cat ideal weight calculator gives a target range for an adult cat.
| Breed | Size | Typical adult weight | Grown by about |
|---|---|---|---|
| Maine Coon | Large | 6–11 kg | 2 to 4 years to finish growing |
| Ragdoll | Large | 5–9 kg | Up to 4 years to finish growing |
| British Shorthair | Medium | 4–8 kg | About 12 months |
| Siamese | Medium | 3–5 kg | About 12 months |
| Bengal | Medium | 4–7 kg | About 12 months |
| Singapura | Small | 2–3 kg | About 12 months |
| Munchkin | Small | 2–4 kg | About 12 months |
How to weigh a kitten and track its growth
Weigh the kitten every two weeks, at the same time of day, on the same scales, and write the number down — the line over weeks is what matters, not any single reading. For a kitten, kitchen scales are often the easiest tool: put the kitten in a basket or a box on the scales, weigh the basket, and take the difference. For a larger kitten, step on the bathroom scales holding the kitten, then step on without it, and take the difference. Plot the weights on a simple chart, or just keep a list with dates: what you are looking for is a smooth, steady rise, not a flat line and not a sudden jump. 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 not growing needs a vet, not just more food.
Body condition is the second check, and it matters as much as the scales. Feel the ribs: you should feel them easily under a thin layer of fat without pressing hard. Look from above for a visible waist behind the ribs, and from the side for a tummy tuck. A kitten should be lean at every age — a roly-poly kitten is not a healthy kitten, and excess weight in kittenhood sets up weight problems for life. If you cannot feel the ribs or there is no waist, the kitten is probably overweight: cut food by about 10%, keep treats under 10% of daily calories, and ask your vet to check growth against the breed's expected adult weight. The kitten cat food calculator guide gives the calorie tables by weight and age, and the cat food calculator works out daily calories by weight and life stage.
When to worry about a kitten's weight
Call your vet promptly if your kitten is losing weight, or not gaining weight over two weeks, or if its ribs are sharp and prominent with no cover, or if it will not eat. Those are all reasons for a vet check, not for simply feeding more — a kitten that is not growing may have worms, a health problem, or a food it does not digest well, and the cause matters more than the calories. Call your vet too if your kitten is gaining weight very fast — much faster than the rough shares in the table above — because rapid growth and excess weight in kittenhood set up weight problems for life. Do not overfeed a kitten to make it grow faster: steady growth matters more than fast growth, and a kitten should stay lean enough that you can feel its ribs easily at every age.
Some kittens are simply small or large for their breed, and that is normal: the breed range is a range, and a kitten at the bottom of it is not necessarily underweight, any more than one at the top is necessarily overweight. What matters is the trend and the body condition, not the single number. A kitten that is gaining steadily, is lean with ribs you can feel, is bright, playful, and eating well, and is inside or near its breed's expected range, is growing well — even if it is smaller than its littermates. A kitten that is gaining in jumps, is hard to feel ribs on, or is dull and reluctant to play, is worth a vet check even if its weight looks reasonable. The cat age calculator and the kitten cat lifespan guide put the kitten's weight in the context of its age and its life, and the adult cat weight calculator guide explains how to track weight once the kitten is grown.
Feeding for healthy kitten growth
Feed a kitten food — one labelled complete and balanced for kittens — in measured amounts, and re-weigh every two weeks, because the amount changes quickly as the kitten grows. Use the resting energy requirement (RER) formula with a factor of about 2.5, applied to the kitten's current weight. For example, a kitten of 2 kg has an RER of about 120 calories, and at the 2.5 factor it needs about 300 calories a day — roughly 85 g of a typical dry food at 350 kcal per 100 g. A kitten of 1 kg needs about 175 calories a day at the same factor. Those are starting points, not prescriptions: a very active kitten needs more than a calm one, and your vet should check growth against the expected adult weight for the breed.
Split the daily amount into three to four meals for a kitten under six months, then two meals a day from about six months. Small, frequent meals suit a kitten's small stomach and fast metabolism, and they make it easier to see appetite changes, which are often the first sign of illness in a kitten. Do not free-feed — leaving a full bowl down all day makes it impossible to know how much the kitten has eaten and hides appetite changes. Keep treats under 10% of daily calories, and do not give milk: most cats cannot digest lactose well, and milk is not a substitute for water. Fresh water should always be available, in a clean bowl, away from the litter tray. If your kitten has a health condition, ask your vet or a veterinary nutritionist before choosing a special diet — therapeutic diets are medicines in food form and should not be chosen by guesswork. The kitten cat food calculator guide gives the full calorie tables by weight and age.
For related reading, see the kitten weight predictor, the kitten cat weight calculator guide, the cat ideal weight calculator, the kitten cat food calculator guide, the kitten age in human years guide, the adult cat weight calculator guide.
Frequently asked questions
How much should my kitten weigh?
It depends on the breed and its size: a small breed is typically 2 to 4 kg as an adult, a medium breed 3 to 6 kg, and a large breed 5 to 11 kg. A Maine Coon is typically 6 to 11 kg, a British Shorthair 4 to 8 kg, and a Singapura 2 to 3 kg. Use the breed range first, the size range second, and body condition to settle the question.
How fast should a kitten gain weight?
Steadily, not in jumps. As a very rough guide, a kitten is about half to two-thirds of its expected adult weight at 6 months, and near its adult weight by 12 months for small and medium breeds — with large breeds such as the Maine Coon still growing at 2 to 4 years. Weigh every two weeks and watch the line, not any single reading.
How much should a Maine Coon kitten weigh at 6 months?
As a very rough guide, about half to two-thirds of its expected adult weight of 6 to 11 kg — so roughly 3 to 7 kg. Maine Coons grow slowly and can take 2 to 4 years to finish growing, so a Maine Coon kitten that is still growing at 12 months is normal. If your kitten is well outside that rough band, ask your vet to check its growth.
How do I know if my kitten is overweight?
Feel the ribs: you should feel them easily under a thin layer of fat without pressing hard. Look from above for a visible waist. If you cannot feel the ribs or there is no waist, the kitten is probably overweight — cut food by about 10% and ask your vet to check growth against the expected adult weight for the breed.
When is a kitten fully grown?
Most cats are adults by about 12 months, but large breeds such as the Maine Coon can take 2 to 4 years to finish growing. A cat is an adult when it has finished growing and its weight has been stable for a few months — ask your vet to confirm it at a routine check.
What if my kitten is not gaining weight?
A kitten that is not gaining weight over two weeks, or that is losing weight, needs a vet check — a kitten that is not growing may have worms, a health problem, or a food it does not digest well. Do not simply feed more: ask your vet to check for the cause first.
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.