CatYearsHow old is your cat in human years?
A 1-year-old cat is about 15 in human years, a 2-year-old about 24 — and after that, each cat year adds roughly 4 human years. Enter your cat’s age below for its human equivalent and life stage.
Life stage: Prime (3–6 years)
Peak adult condition. The big wins at this stage are routine: a yearly vet visit, weight checks, and keeping teeth and play habits in good shape.
The short answer, by age
On the veterinary scale, cats sprint through childhood and then age steadily. A few of the most-asked ages:
| Cat age | Human years | Cat age | Human years |
|---|---|---|---|
| 1 year | 15 | 2 years | 24 |
| 3 years | 28 | 5 years | 36 |
| 7 years | 44 | 10 years | 56 |
| 12 years | 64 | 15 years | 76 |
| 18 years | 88 | 20 years | 96 |
Full table from 1 month to 25 years: the complete cat age chart. Still in the kitten months? The kitten age calculator works in weeks and months.
How the conversion works
Cats do not age on a single multiplier. The scale used here is the one veterinary practices work from, published in the feline life-stage guidelines of the AAHA (American Animal Hospital Association) and AAFP (American Association of Feline Practitioners). It has three pieces: the first year counts as about 15 human years, because a kitten grows from helpless newborn to a sexually mature, fully grown adult in twelve months. The second year adds about 9 more, taking a 2-year-old to roughly 24. From then on, cats age at a steadier pace of about 4 human years per cat year, so the formula for cats over two is simply 24 + 4 × (age − 2).
Kitten months follow the month-by-month values from the same published chart — roughly 1 human year at 1 month, 4 at 3 months, 10 at 6 months and 15 at 12 months. One honest caveat: the published chart gives a 14–15 range at 11 months, so this calculator uses the midpoint, 14.5, and says so.
What the number does — and does not — mean
The human equivalent is a comparison, useful for understanding what stage of life your cat is in and what care typically goes with it. It is not a health measurement. Breed, body condition, whether a cat lives indoors, dental health and plain individual variation all move real ageing around, and none of that is in the arithmetic. A change in appetite, weight, thirst or litter-box habits is a reason to call your vet whatever the chart says.
Have a dog as well? Dogs age differently — size matters a lot — so use the separate Dog Age Calculator rather than this scale.
Life stages at a glance
Common questions
How old is a 1-year-old cat in human years?
About 15. By twelve months a cat is fully grown and sexually mature — far closer to a mid-teenager than to a 7-year-old child, which is what the old “times seven” rule would claim.
How old is a 10-year-old cat in human years?
About 56. A 10-year-old is at the end of the Mature stage — the rough equivalent of a person in their mid-fifties — and is a good candidate for twice-yearly senior screenings soon after.
Do indoor and outdoor cats age at different rates?
The conversion scale is the same, but expected lifespan is not: indoor cats commonly live 12–18 years, while cats that roam freely outdoors often live far shorter lives. More on the cat lifespan page.
How accurate is this calculator?
It reproduces the standard veterinary life-stage scale exactly, but every such scale is an approximation of a biological process that varies by individual. Treat the result as “about”, not as a precise measurement — see the method page for the full breakdown.