PetCalc
Cat Health9 min read

How Big Will My Cat Get? Weight Chart by Age

Most cats reach full size at 12 months and settle at 4-5 kg. See the kitten weight chart, breed sizes, and the signs your cat is still growing.

White long-haired cat looking to the side against a blue background

Cats do not vary in size anything like dogs do — there is no feline equivalent of a chihuahua standing next to a great dane. Almost every domestic cat lands somewhere between 3 and 6 kg, and the ones that go beyond that are nearly always a specific handful of breeds.

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Quick answer

  • • Most cats finish growing at 12 months.
  • • Typical adult weight: 4–5 kg (9–11 lb).
  • • Males run about 1–2 kg heavier than females.
  • • Large breeds keep growing until 3–4 years.
  • • Kittens gain roughly 450 g a month until six months.

Kitten weight chart by age

The simplest guide for the first half year is one pound per month of age. It is rough, but it tracks a healthy kitten surprisingly well:

AgeTypical weightWhat is happening
1 month~0.45 kg / 1 lbJust starting to walk and explore
2 months~0.9 kg / 2 lbWeaned and litter trained
3 months~1.4 kg / 3 lbFast growth; baby teeth complete
4 months~1.8 kg / 4 lbAdult teeth coming through
5 months~2.3 kg / 5 lbNeutering window opens
6 months~2.7 kg / 6 lbRoughly two thirds of adult weight
8 months~3.2 kg / 7 lbGrowth rate slowing
10 months~3.6 kg / 8 lbClose to adult size
12 months~4–4.5 kg / 9–10 lbAdult; frame still filling out

Averages for a domestic shorthair. Large breeds run above these numbers from a few months old, and small breeds below them.

A rough prediction from six months

At six months a kitten is usually around two thirds of its adult weight, which gives you a workable estimate:

adult weight ≈ weight at 6 months × 1.5

A 2.7 kg six-month-old is heading for roughly 4 kg. It is an estimate rather than a promise — breed, genetics and whether the kitten has been well fed all shift the result — but it is far better than guessing from paw size, which tells you very little in cats.

Adult size by breed

Breed is the single biggest factor. These are typical adult weights, and the age by which each breed is usually done growing:

BreedFemaleMaleFully grown by
Singapura2–3 kg2.5–3.5 kg12 months
Devon Rex2.5–3.5 kg3–4 kg12 months
Siamese2.5–4 kg4–5 kg12–18 months
Domestic Shorthair3.5–4.5 kg4.5–6 kg12 months
British Shorthair4–5.5 kg5.5–8 kg3 years
Persian3–4.5 kg4–6 kg18–24 months
Bengal3.5–5 kg5–7 kg18–24 months
Ragdoll4.5–7 kg6.5–9 kg3–4 years
Norwegian Forest4–6 kg6–9 kg3–4 years
Maine Coon4.5–7 kg6–9 kg3–4 years

Signs your cat is still growing

  • Long legs and a lanky look. Adolescent cats grow in height before they fill out, which is why many look gangly at eight or nine months.
  • Steady weight gain month on month rather than a flat line.
  • Still on kitten food and eating a lot. Growing cats genuinely need more calories per kilo than adults do.
  • Under 12 months — or under three years in one of the large breeds.

Once the weight stops climbing for two or three months in a row, your cat has finished. That is the point to switch to adult food and recalculate portions, because kitten food at adult activity levels is how many cats put on their first spare kilo.

Big frame or extra weight? Feel the ribs with light pressure — they should be easy to count under a thin covering. Look down from above for a waist behind the ribs, and from the side the belly should tuck up. A large breed passes all three tests at 7 kg; an overweight cat fails them at 5.

What does not predict size

A few popular shortcuts are worth ignoring. Paw size barely correlates with adult weight in cats, unlike in dogs. Being the biggest of the litter at eight weeks says more about who fed best than about final size. And fur length makes a cat look far larger than it is — plenty of magnificent-looking long-haired cats weigh less than a sleek-looking shorthair.

Growth that stalls is a symptom. A kitten that stops gaining weight, or loses it, needs a vet rather than more food — parasites, infections and congenital problems all show up this way first. The same is true of an adult cat that starts losing weight without a diet change.

The bottom line

Expect most cats to finish at 12 months and land between 4 and 5 kg, with males heavier and large breeds carrying on growing for years. Use the six-month weight × 1.5 estimate for a target, weigh monthly while your cat is growing, and judge the result by body condition rather than the number alone. For daily portions at each stage, the cat food calculator does the maths. 🐱

Frequently Asked Questions

How big will my cat get?

Most domestic cats finish growing at around 12 months and settle between 4 and 5 kg (9–11 lb), with males usually a kilo heavier than females. Breed matters more than anything else: a Singapura may never pass 3 kg while a Maine Coon can reach 8 kg or more.

When do cats stop growing?

Around 12 months for most cats, although the frame keeps filling out until about 18 months. Large breeds are the exception — Maine Coons, Ragdolls, Norwegian Forest Cats and Savannahs commonly keep growing until 3 or even 4 years old.

How much should a kitten weigh?

A useful rule is roughly 450 g (1 lb) per month of age up to about six months: 450 g at one month, 900 g at two, 1.4 kg at three, and so on. After six months the rate slows and most cats add only another kilo or so before their first birthday.

Does neutering affect how big a cat gets?

Slightly. Neutering before the growth plates close can leave a cat a little taller and leaner in frame. What it definitely changes is energy needs, which drop by roughly a quarter — so cats often gain weight after neutering unless portions are adjusted. That is fat, not size.

Is my cat big or overweight?

Use your hands. A big cat still has ribs you can feel easily under a thin layer, a visible waist behind the ribs from above, and a belly that tucks up from the side. If the ribs are hard to find and the waist has gone, that is fat rather than frame — no matter how large the breed.

Do male cats get bigger than females?

Yes, usually by around 1–2 kg in the same breed. A male domestic shorthair typically lands between 4.5 and 6 kg and a female between 3.5 and 4.5 kg. The gap is wider in large breeds, where males can be several kilos heavier.

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