Adult Maine Coon males typically weigh 5.9–10 kg (13–22 lb) and females 4.1–6.8 kg (9–15 lb) (TICA, PetMD, breed growth charts). Most are full grown at 3–5 years (TICA). Two examples from the calculator: a 3-month-old male usually weighs 2–3.2 kg (4.4–7.1 lb), and a 6-month-old female 3.2–4.5 kg (7.1–9.9 lb).
Estimates only. There is no veterinary growth standard for Maine Coons. These ranges combine a published birth-weight study, cattery records, a breed growth chart and registry adult weights. Body condition matters more than the number, so ask your vet if you're unsure.
Maine Coon growth chart by age
This Maine Coon growth chart by age covers males and females from birth to 5 years, so you can check Maine Coon size by age at a glance. Each row is the typical range, not a target: a healthy kitten can sit at either end, and some will sit outside it. What matters most is a steady upward trend and a good body shape. The calculator above reads from this same table and fills in the ages between rows.
| Age | Male (kg) | Male (lb) | Female (kg) | Female (lb) | Growth stage |
|---|---|---|---|---|---|
| Birth | 100–138 g | 3.5–4.9 oz | 100–138 g | 3.5–4.9 oz | Kitten |
| 1 week | 150–250 g | 5.3–8.8 oz | 150–250 g | 5.3–8.8 oz | Kitten |
| 2 weeks | 270–350 g | 9.5–12.3 oz | 270–350 g | 9.5–12.3 oz | Kitten |
| 4 weeks | 500–600 g | 17.6–21.2 oz | 450–550 g | 15.9–19.4 oz | Kitten |
| 8 weeks | 1.2–1.8 kg | 2.6–4 lb | 0.9–1.4 kg | 2–3.1 lb | Kitten |
| 3 months | 2–3.2 kg | 4.4–7.1 lb | 1.6–2.7 kg | 3.5–6 lb | Kitten |
| 4 months | 2.8–3.5 kg | 6.2–7.7 lb | 2.4–3 kg | 5.3–6.6 lb | Kitten |
| 6 months | 4.1–5.4 kg | 9–12 lb | 3.2–4.5 kg | 7.1–9.9 lb | Adolescent |
| 9 months | 5.4–7.3 kg | 12–16 lb | 4.1–5.4 kg | 9–12 lb | Adolescent |
| 12 months | 5.9–8.2 kg | 13–18 lb | 4.1–6.4 kg | 9–14 lb | Young adult, still growing |
| 18 months | 5.9–9.1 kg | 13–20 lb | 4.1–6.8 kg | 9–15 lb | Young adult, still growing |
| 2 years | 5.9–10 kg | 13–22 lb | 4.1–6.8 kg | 9–15 lb | Young adult, still growing |
| 3 years | 5.9–10 kg | 13–22 lb | 4.1–6.8 kg | 9–15 lb | Young adult, still growing |
| 4 years | 5.9–10 kg | 13–22 lb | 4.1–6.8 kg | 9–15 lb | Young adult, still growing |
| 5 years | 5.9–10 kg | 13–22 lb | 4.1–6.8 kg | 9–15 lb | Mature (full grown) |
Think of it as a growth Maine Coon size chart rather than a set of exact milestones. Breeders who weigh whole litters see kittens from the same mother vary by several hundred grams within weeks, and that spread widens as the cats grow. If your cat's weight sits a little above or below its row, check its body condition (see below) before worrying.
Where the numbers come from
- Birth: a 2023 study of 5,596 pedigree kittens in French catteries weighed 892 Maine Coon kittens at birth. Their average was 119 g (standard deviation 19 g), the heaviest of the breeds studied; we use 100–138 g, the average plus or minus one standard deviation.
- 1 week to 4 months: records from a Maine Coon cattery that weighed about 60 kittens. This is breeder data, not a scientific study.
- 8 weeks to 18 months: the growth chart published by Maine Coon Central, a breed blog. Where it overlaps with the cattery (8 weeks and 3 months), we use the wider of the two ranges.
- Adults: TICA's breed profile, checked against PetMD, the CFA and a 2015 study that weighed 81 adult Maine Coons.
Maine Coon kitten growth chart (birth to 12 months)
The first year is when Maine Coon kittens change fastest. The chart below plots the typical weight for males and females from birth to 12 months, with the shaded bands showing the normal range. Use it as a growth chart for Maine Coon kittens alongside your own weekly weigh-ins.
| Age | Male | Female | Male: % of adult weight |
|---|---|---|---|
| Birth | 100–138 g (3.5–4.9 oz) | 100–138 g (3.5–4.9 oz) | 1% |
| 1 week | 150–250 g (5.3–8.8 oz) | 150–250 g (5.3–8.8 oz) | 3% |
| 2 weeks | 270–350 g (9.5–12.3 oz) | 270–350 g (9.5–12.3 oz) | 4% |
| 4 weeks | 500–600 g (17.6–21.2 oz) | 450–550 g (15.9–19.4 oz) | 7% |
| 8 weeks | 1.2–1.8 kg (2.6–4 lb) | 0.9–1.4 kg (2–3.1 lb) | 19% |
| 3 months | 2–3.2 kg (4.4–7.1 lb) | 1.6–2.7 kg (3.5–6 lb) | 33% |
| 4 months | 2.8–3.5 kg (6.2–7.7 lb) | 2.4–3 kg (5.3–6.6 lb) | 40% |
| 6 months | 4.1–5.4 kg (9–12 lb) | 3.2–4.5 kg (7.1–9.9 lb) | 60% |
| 9 months | 5.4–7.3 kg (12–16 lb) | 4.1–5.4 kg (9–12 lb) | 80% |
| 12 months | 5.9–8.2 kg (13–18 lb) | 4.1–6.4 kg (9–14 lb) | 89% |
How fast do Maine Coons grow?
Very fast at first, then slowly for years. In the cattery records, a Maine Coon kitten gains well over half its birth weight in the first week and is about four times heavier by one month. Between 3 and 6 months a male typically climbs from 2–3.2 kg to 4.1–5.4 kg — often the most visible growth spurt, when kittens suddenly look leggy and long. After about 9 months the gains slow down, but unlike most cats the Maine Coon keeps adding frame and muscle into its third, fourth or even fifth year.
Maine Coon kitten size at key ages
- 3 month old Maine Coon weight: males about 2–3.2 kg (4.4–7.1 lb), females about 1.6–2.7 kg (3.5–6 lb). Most kittens go to new homes around this age.
- 6 month old Maine Coon weight: males about 4.1–5.4 kg (9–12 lb), females about 3.2–4.5 kg (7.1–9.9 lb). Many look gangly, with big paws and long tails.
- 1 year old Maine Coon weight: males about 5.9–8.2 kg (13–18 lb), females about 4.1–6.4 kg (9–14 lb). Big, but usually not finished growing.
So this Maine Coon kitten weight chart also explains a common worry: a kitten that seems "small for a Maine Coon" at 10 or 12 weeks is often perfectly normal. Big size shows up later than many owners expect, and Maine Coon kitten size at 3 months is closer to an ordinary kitten's than to a grown Maine Coon's.
Maine Coon weight chart by age (1 to 5 years)
After the first birthday the Maine Coon weight by age curve flattens. The table below shows the Maine Coon weight chart by age from 1 to 5 years. From 2 years the typical range for adults applies, but many cats keep adding muscle and filling out through the chest and shoulders until 3–5 years.
| Age | Male | Female | Growth stage |
|---|---|---|---|
| 12 months | 5.9–8.2 kg (13–18 lb) | 4.1–6.4 kg (9–14 lb) | Young adult, still growing |
| 18 months | 5.9–9.1 kg (13–20 lb) | 4.1–6.8 kg (9–15 lb) | Young adult, still growing |
| 2 years | 5.9–10 kg (13–22 lb) | 4.1–6.8 kg (9–15 lb) | Young adult, still growing |
| 3 years | 5.9–10 kg (13–22 lb) | 4.1–6.8 kg (9–15 lb) | Young adult, still growing |
| 4 years | 5.9–10 kg (13–22 lb) | 4.1–6.8 kg (9–15 lb) | Young adult, still growing |
| 5 years | 5.9–10 kg (13–22 lb) | 4.1–6.8 kg (9–15 lb) | Mature (full grown) |
Notice that the lower end of each range stays at the registry minimum from 12 months on. That is deliberate: TICA describes adult males from 13 lb and females from 9 lb, so a young cat that already weighs as much as many healthy adults isn't underweight just because a growth chart says it "should" be heavier. The upper end keeps rising until about 2 years, then levels off.
How big do Maine Coons get? Full-grown size
Maine Coons are one of the largest domestic cat breeds, but published adult weights vary more than you might expect. The table shows the adult Maine Coon weight given by each source we checked.
| Source | Males | Females | Notes |
|---|---|---|---|
| TICA (breed registry) | 13–18 lb (5.9–8.2 kg) | 9–13 lb (4.1–5.9 kg) | Full size at 3–5 years |
| CFA (breed registry) | Often 20 lb (9.1 kg) or more | "Usually smaller" | Full growth can take up to 3 years |
| PetMD (vet-reviewed) | 18–25 lb (8.2–11.3 kg) | 10–14 lb (4.5–6.4 kg) | Breed profile |
| Maine Coon Central (breed blog) | 18–22 lb (8.2–10 kg) | 12–15 lb (5.4–6.8 kg) | Adults 2–5 years |
| Purina UK (brand profile) | 4.8–8.2 kg (both sexes) | General breed profile | |
| Spada et al. 2015 (study) | 4.9–8.5 kg, mean 6.7 kg (both sexes) | 81 healthy adult blood donors | |
| Range this page uses | 5.9–10 kg (13–22 lb) | 4.1–6.8 kg (9–15 lb) | TICA minimum to blog maximum |
Taken together, a typical Maine Coon full grown weight is about 5.9–10 kg (13–22 lb) for males and 4.1–6.8 kg (9–15 lb) for females. The heaviest figures (PetMD's "up to 25 pounds") describe big, well-muscled males; plenty of healthy Maine Coons are much lighter. The study of 81 healthy adult Maine Coon blood donors found weights from 4.9 to 8.5 kg, with an average of 6.7 kg for males and females together — a useful reality check from cats that were actually weighed.
Maine Coon full grown size: length and height
We found no registry or veterinary source that gives a typical body length or shoulder height for Maine Coons, so we don't quote one. The only verified measurements are record holders (see below). What the breed profiles do describe is the shape: PetMD notes longer bodies than most breeds and much larger heads and paws, and the CFA describes dramatically large ears, typically with prominent tufts. That long frame is why a Maine Coon looks bigger than its weight suggests.
How much should a Maine Coon weigh?
Whatever its body condition says is right. The ranges above tell you what is common, but the right Maine Coon weight for your cat depends on its frame. A big-boned male can be lean at 9 kg, while a fine-boned female can be overweight at 6 kg. Your vet will judge this with a body condition score, explained further down the page.
When do Maine Coons stop growing?
Later than almost any other cat. TICA says Maine Coons develop slowly and "don't achieve their full size until they are three to five years old". The Cat Fanciers' Association says the breed "can take up to three years to reach full growth". Sexual maturity also comes late: a 2025 study of Polish breeding records describes Maine Coons as a late-maturing breed, with puberty at about 10–16 months.
- 0–6 months: rapid growth in weight and length.
- 6–12 months: the lanky adolescent stage — tall and long, not yet broad.
- 1–3 years: slower growth; weight keeps rising, especially in males.
- 3–5 years: final filling out of chest, shoulders and muscle. Most Maine Coons are full grown by now.
So, at what age is a Maine Coon full grown? Usually between 3 and 5 years, with females often finishing earlier than males. Any weight gain after 5 years is likely to be fat rather than growth, which is when a weight check becomes more important. The calculator shows how many months your cat probably has left until it is fully grown.
Male vs female Maine Coon weight
TICA says the size difference between males and females is more marked in Maine Coons than in any other breed. For the first month, male and female kittens weigh about the same. From about 2 months the males pull ahead, and by a year the gap is around 1.8 kg at the middle of the ranges.
- Male Maine Coon weight: about 5.9–10 kg (13–22 lb) as a full-grown adult (TICA minimum to breed-blog maximum); PetMD gives 18–25 lb.
- Female Maine Coon weight: about 4.1–6.8 kg (9–15 lb) as an adult; PetMD gives 10–14 lb.
- At 1 year: males 5.9–8.2 kg (13–18 lb), females 4.1–6.4 kg (9–14 lb).
Both sexes vary a lot. A large female can outweigh a small male, and a cattery that bred the kittens in our 1-week-to-4-month data mentions a female of almost 8 kg. Choose the sex in the calculator to get the matching range.
Is my Maine Coon kitten underweight or overweight?
A growth chart can only tell you whether your cat is typical, not whether it is healthy. Vets use a body condition score instead. On the 9-point WSAVA scale, a score of 5 is ideal: the cat looks well proportioned, you can see a waist behind the ribs from above, the ribs are easy to feel under a slight covering of fat, and there is only a small fat pad on the belly. Lower scores mean visible ribs, spine and hip bones; higher scores mean ribs that are hard to feel and a rounded belly.
Is my Maine Coon kitten underweight?
- Its ribs, spine or hip bones are easy to see, not just feel.
- Its weight has stalled or dropped over two or more weigh-ins.
- It has diarrhoea, vomiting, a poor appetite or less energy than usual.
Any of those deserves a vet visit, whatever the chart says. Very young kittens are especially fragile: a 2024 study of 5,504 kittens in French catteries found that kittens that lost weight, or failed to gain, between birth and day 2 had a higher risk of dying in the first two months. A long, lean adolescent with a good appetite and normal energy, on the other hand, is usually just going through the lanky stage.
Overweight Maine Coon
Big doesn't mean fat, but Maine Coons can and do become overweight. Cornell estimates that about half the cats seen at vet clinics are overweight or obese, with higher risks of diabetes and lameness. For this breed weight matters twice over, because hip dysplasia is common and its severity rises with body mass (Low 2019). If you can't feel the ribs easily or the waist has disappeared, ask your vet for a weight plan rather than cutting food sharply on your own.
What affects Maine Coon growth?
- Genetics and sex: the parents' size is the best guide to a kitten's adult size, and males grow bigger than females. Breeding for size has costs: the hip dysplasia study found a genetic link between body mass and hip dysplasia severity.
- Birth weight and litter size: heavier kittens at birth tend to do better, and breeders report lighter kittens in bigger litters.
- Diet: a complete kitten food matched to growth. Maine Coons grow for longer than most cats, so ask your vet when to switch to adult food rather than switching automatically at 12 months.
- Neutering timing: in a 1997 study, cats neutered at 7 weeks or 7 months had growth plates that closed later and slightly longer leg bones than cats left entire. A 2017 study of Maine Coons with slipped capital femoral epiphysis suggested that neutering, delayed growth-plate closure and high body weight may all play a part. Discuss timing with your vet; neutering also has clear health benefits.
- Health: parasites, infections and inherited diseases such as SMA (which causes muscle weakness from about 3–4 months) can all slow growth. Unexplained poor growth is always a reason to see a vet.
Maine Coon size vs other cat breeds
How does a Maine Coon vs regular cat size compare? An average house cat weighs 8–12 lb, most around 10 lb (PetMD), so a big male Maine Coon can weigh twice as much. Other large longhaired breeds come closer.
| Breed | Typical adult weight | Full size reached |
|---|---|---|
| Maine Coon | Males 18–25 lb, females 10–14 lb (PetMD); TICA 13–18 / 9–13 lb | 3–5 years (TICA) |
| Average house cat | 8–12 lb, most about 10 lb (PetMD) — see our kitten age estimator | By young adulthood, 1–5 years (PetMD) |
| Norwegian Forest Cat | Typically 12–15 lb; females from 8 lb, some males 19 lb+ (PetMD) | Not stated |
| Siberian | 12–15 lb or more (PetMD) | Around 5 years (PetMD) |
| Ragdoll | Up to about 20 lb (PetMD) | About 4 years (CFA) |
| British Shorthair | Males up to 17 lb, females up to 12 lb (PetMD) | 3–4 years (PetMD) |
| Bengal | About 8–15 lb depending on generation (PetMD) | Not stated |
| Persian | 7–13 lb (PetMD) | Not stated |
Weight isn't the whole story. Maine Coons are long, tall cats with a lot of coat, so they look even bigger than the scale says. For how long these big cats live, see the Maine Coon lifespan calculator.
The biggest Maine Coons on record
Guinness World Records measures cats by length, from nose to tail tip, rather than by weight, and Maine Coons have held the record for the longest domestic cat since 2010:
- Longest domestic cat ever: Mymains Stewart Gilligan ("Stewie"), a Maine Coon, measured 123 cm (48.5 in) on 28 August 2010.
- Longest domestic cat living: Barivel, a Maine Coon from Vigevano, Italy, measured 120 cm (3 ft 11.2 in) on 22 May 2018, when he was two years old.
We found no verified record for the heaviest Maine Coon. Claims of 15 kg-plus Maine Coons online can't be checked and may describe overweight cats — which, for a breed prone to hip dysplasia, is nothing to celebrate. The biggest Maine Coon that matters is a healthy one.
How this Maine Coon growth calculator works
Age → expected weight: enter an age in weeks, months or years and choose male or female. The calculator reads the table at the top of this page and draws a straight line between the nearest two rows, so a 5-month-old male gets a range between the 4- and 6-month rows. It also shows the growth stage, how much of the typical adult weight the middle of the range represents (a 6-month-old male is at about 60%), and how many months are likely to remain until full size at 3–5 years. Ages from 5 years use the adult range.
Is my Maine Coon on track? Add your cat's weight in kg or lb. The calculator says whether it is below, within or above the typical range for its age and sex, how far outside the range it is, and marks its position on a bar. A 6-month-old male weighing 3.5 kg, for example, is 0.6 kg below the 4.1–5.4 kg range. Weights that can't belong to a Maine Coon, or that are wildly out of line with the age, show a "please check" message instead, because they are usually a unit mix-up.
Limits: the ranges come partly from breeders and a breed blog, not a veterinary standard, so they describe what is typical rather than what is healthy. The calculator can't see your cat's body condition. For the age in human terms, use the Maine Coon age calculator.
Frequently asked questions
How much should a 6 month old Maine Coon weigh?
Typically 4.1–5.4 kg (9–12 lb) for a male and 3.2–4.5 kg (7.1–9.9 lb) for a female. Body condition matters more than hitting the exact range.
How much should a 3 month old Maine Coon weigh?
About 2–3.2 kg (4.4–7.1 lb) for a male and 1.6–2.7 kg (3.5–6 lb) for a female.
How much does a 1 year old Maine Coon weigh?
Usually 5.9–8.2 kg (13–18 lb) for a male and 4.1–6.4 kg (9–14 lb) for a female. Most are still growing at this age.
When is a Maine Coon fully grown?
Usually at 3–5 years. TICA says Maine Coons don't reach full size until three to five years old, and the CFA says growth can take up to three years.
How big do Maine Coons get?
Adult males typically weigh 5.9–10 kg (13–22 lb) and females 4.1–6.8 kg (9–15 lb). The longest Maine Coon on record, Stewie, measured 123 cm (48.5 in) from nose to tail tip.
How much does a male Maine Coon weigh?
About 5.9–10 kg (13–22 lb) as an adult (TICA's minimum to a breed-blog maximum). PetMD gives 18–25 lb for males.
How much does a female Maine Coon weigh?
About 4.1–6.8 kg (9–15 lb) as an adult. PetMD gives 10–14 lb and TICA 9–13 lb.
Is my Maine Coon kitten too small?
Not necessarily. Maine Coons grow slowly for years and look ordinary-sized at 3 months. Check that it is gaining steadily, eating well and has a good body condition; see a vet if its weight stalls or drops, or if it seems unwell.
How much should a Maine Coon kitten weigh at birth?
About 100–138 g. A 2023 study of 892 Maine Coon kittens found an average birth weight of 119 g, the highest of the breeds studied.
How fast do Maine Coon kittens grow?
Fastest in the first 6 months: a male typically goes from about 2–3.2 kg at 3 months to 4.1–5.4 kg at 6 months. Growth then slows but continues until 3–5 years.
When do Maine Coons stop growing?
Most stop growing between 3 and 5 years. Weight gain after about 5 years usually means fat rather than growth.
Is my Maine Coon overweight?
Feel the ribs and look for a waist from above. On the WSAVA 9-point scale, 5 is ideal: ribs easy to feel under a slight fat cover and a visible waist. If the ribs are hard to feel, ask your vet for a weight plan.
How big is a Maine Coon compared with a normal cat?
An average house cat weighs 8–12 lb (PetMD), while a male Maine Coon is often 18 lb or more, so a big male can weigh about twice as much.
What is the biggest Maine Coon ever?
The longest was Mymains Stewart Gilligan (Stewie) at 123 cm (48.5 in) in 2010; the longest living is Barivel at 120 cm (Guinness World Records). Guinness doesn't record the heaviest cat.
This calculator gives an estimate for education and fun. Every pet ages differently — for health decisions, talk to your veterinarian.