Overview
Most kittens reach full size between 12 and 18 months, but their growth can reveal early signs of health issues too. Research shows that kittens who gain weight too fast are more likely to become overweight adults, while regular weighing can help spot potential illnesses early. Kitten growth doesn’t happen all at once, and it varies between breeds.
From birth to eight weeks: Newborn phase
Two to six months: playful, growing fast
Six to 12 months: looking grown-up
Beyond 12 months: when growth stops
Kitten growth timeline at a glance
What science says about helping your kitten grow
Medically reviewed by
Published on 15/05/2025 • Reviewed on 15/05/2025