Maine Coon growth chart: the four milestones that are actually measured

No registry, university or veterinary body publishes a Maine Coon growth chart. Month-by-month charts online are unsourced and disagree with each other. Here is what science actually has: four anchors, with their studies.

Pick an age, get the honest answer12 months

Around 1 year (a measured anchor)

5.5 kg median (12.1 lb)

42 healthy US breeder-owned cats, owner-reported (Freeman et al. 2013): median 5.5 kg at 1 year, healthy range 3.6 to 7.5 kg (7.9 to 16.5 lb). A 9 lb yearling can be exactly on track.

This explorer reports measured studies about the breed in general. It never judges an individual cat: only a vet with your cat on the scale can do that.

The four measured growth anchors

1.Birth

115 g mean

about 2.3% of an adult female's weight

German breeder data (Moik & Kienzle 2011). The same paper's only other growth point: bigger breeds grow faster in absolute terms up to 12 weeks.

2.1 year

5.5 kg median (12.1 lb)

range 3.6 to 7.5 kg (7.9 to 16.5 lb)

42 healthy US breeder-owned cats, owner-reported weights (Freeman et al. 2013). Half of healthy yearlings sat below 12 lb.

3.About 21 months

7.5 kg mean (16.5 lb)

range 5.3 to 9.3 kg (11.7 to 20.5 lb)

A young, male-heavy CLINICAL sample (16 of 17 were male orthopaedic patients; Borak et al. 2017). It shows a lean young male CAN weigh 16.5 lb, never that yours should.

4.Adult (over 2 years)

5.6 to 6.7 kg by study (12.3 to 14.8 lb)

median 5.6 kg US (Freeman 2013), mean 6.25 kg Austria (Schnabl-Feichter 2018), mean 6.7 kg Italy (Spada 2015)

Three healthy adult cohorts from three countries, sexes pooled. The frame keeps filling out afterwards: registries put full maturity at three to five years, depending on the source.

Why only four? Because these are the only growth figures with a published, named study behind them. Everything between the anchors is unmeasured, and we will not invent a curve where none exists. Full weight context lives on our Maine Coon size page.

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Read body condition, not the scale

With healthy yearlings spanning 3.6 to 7.5 kg in the same study, a single "target weight" for your cat's age is meaningless. What vets actually read is body condition, scored 1 to 9, where 5 is ideal. In the one study that weighed only ideal-condition cats (Kienzle & Moik 2011), Maine Coons still topped the scale as the "giant" class: big is normal for this breed. Round is the thing to watch. In general, for a cat at a healthy 5/9:

You can feel the ribs under a light fat cover without pressing hard.
Seen from above, there is a visible waist behind the ribs, even under all that coat.
Seen from the side, the belly tucks up rather than sagging in a pouch (a modest primordial pouch is normal).

This describes cats in general, never a verdict on yours: coat depth and frame size make Maine Coons genuinely hard to score by eye, so when in doubt, ask your vet to put a number on it at the next visit.

This is information, not veterinary advice, and it cannot tell you what is wrong with your cat. Our rule is a simple one: if something is wrong with your cat, call your vet, and call an emergency clinic if it is out of hours. Nothing you read here is a reason to wait.

Frequently asked questions

+When do Maine Coons stop growing?

Registries place full maturity anywhere from three to five years, depending on the source (TICA's narrative says up to four, its 2025 standard says four to five, CFA says four, GCCF up to three). Skeletal growth plates in the breed have been reported still open well past a general cat's 12.8-month average.

+How big should a Maine Coon be at 6 months?

Honestly: nobody has published a measured answer. No sourced data point exists between birth and the 1-year mark, which is exactly why every month-by-month chart you meet online is invented. If a 6-month figure matters to you (for example, your kitten seems small), that is a question for your vet with the kitten on the scale.

+What should a Maine Coon weigh at 1 year?

In the only measured cohort (42 healthy US breeder-owned cats, Freeman et al. 2013), the median was 5.5 kg (12.1 lb), and the healthy range ran from 3.6 to 7.5 kg. A yearling at 9 lb can be exactly on track: the breed finishes growing years later.

+Is my Maine Coon overweight?

Weight alone cannot answer that in a breed this size-variable: body condition can. Feel for the ribs and look for a waist (see the reader above). If the ribs are hard to find or you are unsure, ask your vet for a body condition score. Nothing on this page is a verdict on your cat.