how long do cats grow?
Cats typically reach their full adult size and weight between 12 and 18 months of age, though skeletal growth largely completes by 9-12 months.
- 1Most domestic cats achieve skeletal maturity, meaning bone lengthening largely ceases, by 9-12 months of age.
- 2Full adult weight and muscle development are generally reached between 12 and 18 months for most cat breeds.
- 3Large cat breeds, such as Maine Coons, are an exception and can continue to grow and fill out until 3-4 years old.
- 4Kittens experience rapid growth, often doubling their birth weight in the first week and gaining approximately one pound per month until 4-5 months of age.
Detailed Answer
Cats generally complete their primary growth phases within their first year to 18 months of life. Skeletal growth, particularly bone lengthening, largely finishes by 9 to 12 months of age for most domestic shorthair and medium-sized breeds. During this period, kittens experience rapid development, gaining significant weight and height.
While bone growth may slow, cats continue to fill out, gaining muscle mass and reaching their full adult weight between 12 and 18 months. This "filling out" phase contributes to their mature physique. Nutrition plays a critical role during this entire growth period; a high-quality, complete, and balanced diet formulated for kittens is essential for proper development.
It's important to note that larger breeds, like Maine Coons or Norwegian Forest Cats, are exceptions and can take significantly longer to reach their full size, sometimes continuing to grow and mature until they are 3 to 4 years old. Monitoring a kitten's growth with regular veterinary check-ups ensures they are developing appropriately.
Warning: Stunted growth or unusually rapid growth can indicate underlying health issues. Consult your veterinarian if you have concerns about your cat's growth trajectory or weight.
Published: July 4, 2026