A cat grows up in two years
Kittens develop astonishingly fast. By six months a cat is like a ten-year-old child, by its first birthday it is like a 15-year-old, and by two it is a young adult in its mid twenties. From then on the pace settles to about four human years for every cat year. That is why the old idea of multiplying by seven does not work for cats: it makes young cats far too young and old cats far too old.
The arc above shows the six life stages that vets use, from kitten to super senior. The cat marker shows where you would be if you were a cat, or where your own cat is now. Each stage brings different needs, from vaccinations and play in the early years to regular check-ups for kidney, thyroid and joint health later on.
How we calculate it
We use the cat age chart published by International Cat Care. It maps 1 month to 1 human year, 6 months to 10, 1 year to 15, 18 months to 21 and 2 years to 24, then adds 4 human years for every cat year after that. Between the points on the chart we draw a straight line. To convert your own age into cat years, we read the chart backwards.
| Cat age | Human equivalent | Life stage |
|---|---|---|
| 6 months | 10 | Kitten |
| 1 year | 15 | Junior |
| 2 years | 24 | Junior |
| 5 years | 36 | Prime |
| 10 years | 56 | Mature |
| 14 years | 72 | Senior |
| 18 years | 88 | Super senior |
Worked example. A person who is 36 and a half would be a cat of about 5.1, right in the prime of life. A cat born on 20 March 2017 was 9.6 years old on 30 October 2026, which is like a person of about 54, in the mature stage.
Helping a cat age well
Cats are good at hiding discomfort, so changes in an older cat, such as drinking more, sleeping in new places or grooming less, are worth mentioning to a vet. From the mature stage onwards, many vets suggest a check-up every six months rather than once a year.
Questions people ask
How many human years is one cat year?
It changes with age. A cat’s first year is like 15 human years and its second adds about nine more, so a two-year-old cat is like a 24-year-old person. After that each cat year equals about four human years.
What are the life stages of a cat?
Vets and cat charities commonly use six: kitten (up to 6 months), junior (7 months to 2 years), prime (3 to 6), mature (7 to 10), senior (11 to 14) and super senior (15 and over).
How long do cats live?
Many pet cats live to between 12 and 18 years, and indoor cats often live longer than cats that roam outside. The oldest cat on record, Creme Puff from Texas, reached 38.
Is anything saved?
Your own birthday is remembered on this device. Your cat’s birthday stays only while the page is open.
Sources. International Cat Care cat age chart; AAHA/AAFP Feline Life Stage Guidelines (2021); Guinness World Records. Calculations run in your browser; nothing you enter is sent anywhere.