— projected growth curve · shaded = likely range (±12%) · ● your kitten today
The rough method: double the 16-week weight
A popular rule of thumb says a cat's adult weight is roughly double its weight at 16 weeks (4 months): ≈ 8.0 lb. It's a fine ballpark for an average-framed cat (who really is about halfway grown at 16 weeks), but it under-predicts large, slow-maturing breeds like Maine Coons and Ragdolls, which are only about a third grown at 4 months and keep filling out for years. The calculator above uses full growth-curve percentages instead, which is why the two answers can differ.
Estimates assume a typical growth pattern; large/slow-maturing breeds keep filling out to 3–4 years. Your vet's growth check is the gold standard.
🧰 More free cat tools
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Cat years → human years, vet-based.
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🐾Pregnancy Calculator
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📖Kitten growth chart
Week-by-week weights from birth to adult.