Want the exact number for your own cat, months included? Use the free cat-to-human-years calculator — pick "Cat," enter an age, and it converts cat years to human years instantly. The chart below covers whole years.
How cat years work
Cats mature very fast at first, then settle into a steady rate. The conversion used by International Cat Care (and echoed by Purina): the first cat year equals about 15 human years, two cat years equal about 24, and every year after that adds about 4 human years. Unlike dogs, size barely matters — most cats are cat-sized.
Cat age chart
This cat age chart converts cat years to human years for every age from 1 to 20.
| Cat age | Human years | Cat age | Human years |
|---|---|---|---|
| 1 | 15 | 11 | 60 |
| 2 | 24 | 12 | 64 |
| 3 | 28 | 13 | 68 |
| 4 | 32 | 14 | 72 |
| 5 | 36 | 15 | 76 |
| 6 | 40 | 16 | 80 |
| 7 | 44 | 17 | 84 |
| 8 | 48 | 18 | 88 |
| 9 | 52 | 19 | 92 |
| 10 | 56 | 20 | 96 |
Beyond 20, keep adding 4 per year — a 25-year-old cat is around 116 human years, which is why they're rare and famous.
Quick answers: cat years → human years
- A 10-year-old cat is about 56 in human years — a mature adult edging toward senior.
- A 13-year-old cat is about 68 human years.
- A 15-year-old cat is about 76 human years — a healthy senior.
- An 18-year-old cat is about 88 human years, and a rare one.
Human years to cat years
Going the other way — human years to cat years — just reverses the same International Cat Care rule. About 15 human years is one cat year, 24 is two, and every extra cat year adds four human years:
| Human years | Cat age |
|---|---|
| 15 | 1 |
| 24 | 2 |
| 28 | 3 |
| 36 | 5 |
| 44 | 7 |
| 56 | 10 |
| 60 | 11 |
Small human-year numbers land inside a cat's first year, which runs fast and linear: a cat reaches roughly 15 human-equivalent years by its first birthday. So 11 human-equivalent years is about a 9-month-old kitten, and 14 is a cat just shy of one. (Inferred: linear scaling across the first year, the same simplification the calculator uses under age one.)
- 1 human-equivalent year is about a 3-week-old kitten.
- 11 human-equivalent years is about a 9-month-old kitten.
Feline life stages
The 2021 AAHA/AAFP Feline Life Stage Guidelines define four stages:
| Stage | Cat age | Human-equivalent |
|---|---|---|
| Kitten | 0–1 year | 0–15 |
| Young adult | 1–6 years | 15–40 |
| Mature adult | 7–10 years | 44–56 |
| Senior | over 10 years | 60+ |
From the mature-adult stage on, vets generally recommend more frequent checkups — aging cats hide illness well, and "senior" is a screening signal, not a verdict.
Common questions
How old is a cat in human years?
Multiply out the International Cat Care rule: 15 for the first year, 24 by the end of the second,
then 4 more each year after. A typical indoor cat lives into its high teens — around 76–88 human
years.
What is 10 years in cat years?
A cat that's lived 10 years is about 56 in human terms. (If you mean a 10-year-old human, that's
a kitten well under one — see the reverse chart above.)
Is there a cat years converter?
Yes — the calculator on the home page does cat years to human years for
any age, including months.