Cat age calculator in human years
A cat reaches the equivalent of 15 human years in its first year and 24 in its second, then adds about 4 years for each year.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter cat age.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
6 months = 10, 1 year = 15, 2 years = 24, then human years = 24 + 4 × (age - 2) up to 21 years (= 100). Stage per the 2021 AAHA/AAFP guidelines: kitten under 1, young adult 1 to 6, mature adult 7 to 10, senior over 10.
Example
Inputs: Cat age = 5 years. Result: Age in human years: 36 years; Life stage: Young adult.
Limits and caveats
- The figures are a general guide; health and lifestyle change real ageing.
- The chart stops at 21 years.
Questions about this tool
How many human years is one cat year?
The first year is about 15 and the second brings the cat to 24, then each later year is about 4.
When is a cat a senior?
Under the 2021 AAHA and AAFP guidelines a cat is senior after age 10, when more regular vet checks are advised.
Where does the chart come from?
The feline life stage guidelines of the American Association of Feline Practitioners (AAFP) and AAHA, as in the age chart published by AAHA.