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Maine Coon Weight Chart — Kitten to 25 lb Gentle Giant

The largest domestic cat breed. Adult males weigh 15–25 lb; females 10–15 lb. Maine Coons are fully grown only by 3–5 years, not 1–2 like most cats. Track your cat's growth with breed-specific percentiles.

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Expected adult weight — male
15-25 lb
Maturity: 48 months (typical cat: 12-18). Lifespan: 12-15 years. Largest domestic cat breed. Fully grown at 3-5 years (vs 1-2 for most). HCM (cardiomyopathy) screening recommended annually.

How to use the Maine Coon weight chart

  1. Pick gender — Males are typically 50 % heavier than females at every age.
  2. Enter current age — Calculator tracks growth 0–48 months.
  3. Compare to expected range — Output shows 10th–90th percentile band for age.
  4. Schedule HCM screening — Annual echocardiogram starting age 2 — the breed's single most important health test.

Maine Coon growth curve — why they take 3–5 years to mature

Unlike most domestic cat breeds — which reach adult weight within 12–18 months — Maine Coons have a protracted growth curve more reminiscent of large-breed dogs. Growth-plate closure radiographs show that many Maine Coons still have open growth plates at 36 months of age, explaining the continued weight gain through years 3–5. This long maturation is why kitten/growth formulas should be continued well past the standard 12-month cut-off other breeds observe.

Expected weight trajectory by month (males shown; females approximately 70 % of male weight at every age):

AgeMale (lb)Female (lb)
2 months2.0–3.51.5–2.8
4 months4.5–6.53.5–5.0
6 months7.0–9.55.5–7.5
12 months11–148–10
24 months14–189–12
36 months16–2210–14
48+ months (adult)15–2510–15

Hypertrophic cardiomyopathy — the Maine Coon's defining health risk

Maine Coons carry a breed-specific MYBPC3 (myosin-binding protein C) mutation that predisposes them to hypertrophic cardiomyopathy (HCM), a progressive thickening of the left ventricular wall. Estimated prevalence in the breed is 30–35 % of cats; homozygous MYBPC3 individuals are near-certain to develop clinical HCM, while heterozygotes have moderate risk.

HCM is often asymptomatic until sudden cardiac events — aortic thromboembolism, congestive heart failure, or sudden death. Screening is straightforward:

  • Genetic test (mail-in, $50): Detects the MYBPC3 mutation. Reputable breeders test all breeding adults; prospective owners can request results.
  • Annual echocardiogram from age 2: Detects left ventricular wall thickening even before symptoms appear. Vet cardiologist exam costs $300–$600.
  • NT-proBNP blood test: Elevated in cats with HCM. Useful as an adjunct but not a replacement for echocardiogram.

Early HCM detection allows pre-symptomatic treatment with atenolol, pimobendan, or other cardiac medications that can extend healthy life by 3–5+ years.

Frequently Asked Questions

How much should a Maine Coon weigh at each age?

Adult males: 15–25 lb. Adult females: 10–15 lb. This is the largest domestic cat breed by body mass and length. Unusually for a cat breed, Maine Coons continue growing until 3–5 years old — most cats are full-grown by 1–2. An 18-month-old Maine Coon at 12 lb is still a kitten and will likely add 3–10 more pounds by age 4.

Why are Maine Coons so large compared to other cats?

Maine Coons evolved in the harsh winters of the northeastern United States (Maine specifically) and were selected over generations for large body mass that conserves heat. Their long rectangular build, heavy bone, and muscular frame — not fat — create their signature “gentle giant” appearance. A healthy Maine Coon at 22 lb has the body composition of a much smaller cat; the mass is genuine lean muscle and bone.

Is my Maine Coon overweight or just big?

Use body condition score (BCS 1–9, with 4–5 ideal), not just weight. A Maine Coon with visible waist tuck, ribs palpable but not prominent, and no abdominal fat pad is healthy at any breed-typical weight. A Maine Coon at 16 lb with no waist tuck and obvious belly paunch is overweight. Maine Coons are NOT supposed to be round — they're long-bodied and rectangular.

What health problems are Maine Coons prone to?

The breed's most important health concern is hypertrophic cardiomyopathy (HCM) — a genetic heart disease caused by the MYBPC3 mutation specifically identified in the breed. Annual echocardiogram screening from age 2 is the veterinary standard. Other predispositions: hip dysplasia (unusual in cats but documented in Maine Coons), spinal muscular atrophy (rare), polycystic kidney disease (less common than in Persians).

How fast do Maine Coon kittens grow?

Maine Coon kittens gain roughly 1.1–1.3 lb per month from 8 weeks to 10 months, then slow to 0.2–0.5 lb per month through year 2, and minimal monthly gains thereafter. Expect about 8–12 lb by 12 months, 12–16 lb by 24 months, and full adult weight by 3–5 years. Use the calculator for your kitten's specific gender and birthdate to see expected weight by age.

How much should I feed a Maine Coon to maintain ideal weight?

Adult Maine Coons need 24–35 kcal/lb/day, or roughly 280–550 kcal for a 12–18 lb cat. Because they're still growing through age 3–5, feed kitten formula until growth plates close (typically confirmed by vet radiograph or stable weight). Use our cat calorie calculator with the Maine Coon adjustment. Overfeeding is the #1 cause of Maine Coon obesity because owners underestimate how long they keep growing.

How long do Maine Coons live?

Average lifespan: 12–15 years. Well-cared-for Maine Coons with genetic HCM screening and weight management routinely live to 16–18 years. Onset of HCM is the most common early-life-ending cause; hypertrophic cardiomyopathy is often asymptomatic until a sudden episode, making screening echos essential.

Sources & References

  1. [1]
    Maine Coon Breed Standard — Cat Fanciers' Association
  2. [2]
    Maine Coon Breed Profile (TICA) — The International Cat Association
  3. [3]
    Feline Hypertrophic Cardiomyopathy in Maine Coons — American College of Veterinary Internal Medicine
  4. [4]
    Body Condition Score System for Cats — WSAVA Global Nutrition Guidelines