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Cat Age Calculator

Free cat age calculator: convert cat years to human years on the veterinary curve and see the life stage — kitten, junior, prime, mature, senior or geriatric.

YOUR WORKSPACEFree to use. No sign-up.
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Enter your cat's age, then press Convert.

An approximation on the widely used veterinary curve — not a medical measure. Individual cats vary.

Deep dive guides

A LITTLE CONTEXT · 4 MIN READCat Years: The Real Curve From Kitten to Geriatric
All 3 related guides

How cat age calculator works

Cats age on a well-established curve: about 10 human years by six months, 15 by the first birthday, 24 by the second, and then a steady +4 human years per cat year after that. The first two years compress a cat's entire childhood and adolescence; a two-year-old cat is roughly a 24-year-old human — fully adult. The calculator converts any age in years and months onto this curve.

The result also names the life stage using International Cat Care's six-stage scheme, which vets use to tailor care: kitten (0–6 months), junior (6 months–2 years), prime (3–6 years), mature (7–10 years), senior (11–14 years) and geriatric (15+). Each stage comes with what it means in practice — from first vaccines in kittenhood to twice-yearly check-ups for seniors.

For contrast, the old "multiply by 7" folk rule is shown too, and the gap is instructive: a 10-year-old cat is about 56 in human years, not 70, because cats hold a long, stable adulthood after their fast first two years. Indoor cats commonly reach their late teens — a 20-year-old cat is about 96 in human terms — which is why senior and geriatric care matter so much.

Frequently asked questions

How do cat years convert to human years?
The standard veterinary curve: 10 human years at six months, 15 at one year, 24 at two years, then +4 human years per cat year. A 5-year-old cat is about 36 in human years, a 10-year-old about 56, and a 15-year-old about 76. Kittens age fastest of all — a four-month-old kitten is roughly a six- or seven-year-old child.
What are the cat life stages?
International Cat Care defines six: kitten (0–6 months), junior (6 months–2 years), prime (3–6 years), mature (7–10 years), senior (11–14 years) and geriatric (15+). The stages matter because care changes with them — vaccination and socialisation while a kitten, weight and dental watch through prime, and twice-yearly vet checks from senior onward.
Why is a 6-month-old kitten "10" in human years?
Kittens develop extraordinarily fast: by six months they are weaned, fully mobile, learning to hunt and near adult size. That burst of development is why the curve rises steeply in the first half-year (about 20 human years per cat year), then levels into the long, stable adulthood that follows.
Is the "×7" rule accurate for cats?
No. It overstates adult cats: a 10-year-old cat is about 56 in human years, not 70, because cats age only +4 human years per year after age two. The rule also understates kittens, who race through more human development in their first year than ×7 can express.
When should a cat start senior vet checks?
From about 11 years old, with check-ups moving to twice a year — kidney disease, hyperthyroidism, arthritis and dental disease all become common in senior and geriatric cats and are far more manageable when caught early. Many "slowing down" cats are actually in treatable pain, so age-related change is worth a conversation with your vet.

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