Large Cat Breeds: Which Grow Biggest and How Big They Get

The largest cat breeds are the Maine Coon, Ragdoll and RagaMuffin, whose mature males can reach about 20 pounds, followed by the Norwegian Forest Cat, Siberian and British Shorthair. The Cat Fanciers’ Association calls the Maine Coon the largest pedigreed cat. Big breeds also grow slowly, taking three to five years to reach full size.

Those two facts, weight and slow growth, are why gear bought for the first year often has to be replaced. A litter box that fits a seven-month-old Maine Coon can be cramped two years later, and a cat tree rated for an average cat may wobble under a 20-pound adult. This section collects what the breed registries say about size, so you can plan for the grown cat rather than the one in front of you.

How big do the large breeds get?

The figures below come from each breed’s profile at the Cat Fanciers’ Association (CFA), the largest registry of pedigreed cats. CFA does not give a female range for every breed, so some cells say only what the registry says.

Two notes on reading the table. First, the registry calls the Siberian “medium to medium large” and describes the British Shorthair by its build (“compact, well-balanced and powerful”) rather than as large. Both are on this list because their males reach weights well above many household cats, and because owners of both ask the same sizing questions. Second, the American Bobtail is described by CFA as “medium to large” and maturing over three years, but the registry gives no weight range, so it is not in the table.

Cat trees built for heavy breeds

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Which breed is the biggest?

The Maine Coon, by the registry’s own words: CFA calls it “the largest of all pedigreed cats.” It is a long, rectangular cat with a heavy coat, large tufted paws and a long tail, so it looks even bigger than its weight suggests. Our page on how big Maine Coons get covers its size, growth and lifespan in detail.

The Ragdoll is the closest rival on weight. CFA describes it as “one of the larger breeds of cat” and gives the same 20-pound figure for mature males. Its coat is softer and lies flatter, with no significant undercoat, so a Ragdoll and a Maine Coon of the same weight can look quite different.

Which large breeds look alike?

Three long-haired breeds get confused most often: the Maine Coon, the Norwegian Forest Cat and the Siberian. All three have heavy coats, ruffs and big tails. The registry standards separate them mainly by the head. The Maine Coon has a square muzzle and a slightly concave profile, the Norwegian Forest Cat a triangular head with a straight profile, and the Siberian a rounded, modified wedge with a gentle slope to the nose. The side-by-side page on Maine Coon vs Norwegian Forest Cat sets the two standards next to each other.

The Ragdoll and RagaMuffin are a second pair. Both are large, calm, semi-longhaired cats; CFA describes the RagaMuffin as “a cuddly, feline teddy bear” with substantial bone, and the Ragdoll as gentle, calm and sociable.

Is my cat a large breed, or just a big cat?

Plenty of big cats have no pedigree. A long-haired household cat with a ruff and tufted ears may look like a Maine Coon, and a heavy shorthair may look like a British Shorthair, but only registration papers confirm a breed. The registry standards describe the ideal show cat, not every cat that shares some of its features.

For buying gear, it does not matter. A 17-pound household cat needs the same litter box length, tree stability and carrier room as a 17-pound pedigreed one. Measure the cat you have: body length from nose to base of tail, and weight. Those two numbers decide more than the breed name does.

What the size means for gear

A full-grown cat of 15 to 20 pounds changes four purchases more than any other:

• Litter boxes. Box size is set by the cat’s body length. The litter box guide explains the sizing rule veterinary behavior guidelines use.
• Cat trees. A heavy cat needs a wide base, thick posts and deep perches. See cat trees for large cats.
• Carriers. A carrier has to let a big cat stand and turn around. See carriers for large cats.
• Grooming. Most of the big breeds are long-haired, and the coat is a daily or weekly job. See grooming a Maine Coon.

Large breeds also have health questions of their own, from heart screening to hips. The care section covers them from veterinary sources.

A note on Savannah cats

Savannah cats are often listed with the big breeds. We have not yet sourced registry size figures for them, and the rules on owning one vary by state and city. If you are considering a Savannah, check your state and local rules first.

We do not link breeders, kittens or prices anywhere on this site. For breed standards, the registries are the place to go.