Cat Health UK

Cat Age Calculator: Cat Years to Human Years

Based on International Cat Care age guidance

Your cat's age

Cat Age Chart

The chart below uses the same age guidance as the calculator, so the two always agree. Ages between the points shown follow the same pattern the calculator uses.

Cat AgeHuman Age
BirthBirth
2 months2 years
3 months4 years
4 months6 years
5 months8 years
6 months10 years
7 months12 years
1 year15 years
18 months21 years
2 years24 years
3 years28 years
4 years32 years
5 years36 years
6 years40 years
7 years44 years
8 years48 years
9 years52 years
10 years56 years
11 years60 years
12 years64 years
13 years68 years
14 years72 years
15 years76 years
16 years80 years
17 years84 years
18 years88 years
19 years92 years
20 years96 years
21 years100 years
22 years104 years
23 years108 years
24 years112 years
25 years116 years

Source: International Cat Care

How Cat Years Work

Cats mature very quickly during their first year of life. In the age system used by this calculator — based on International Cat Care guidance — one cat year is roughly equivalent to 15 human years, and two cat years are approximately 24 human years. After age two, the pace settles: each additional cat year is roughly equivalent to four human years. So a three-year-old cat is about 28 in human terms, a seven-year-old about 44, and a fifteen-year-old about 76.

This front-loaded pattern reflects how quickly kittens develop — cats reach physical and behavioural maturity far sooner than human children. Because those early months matter so much, the calculator also accepts ages in months for kittens under one year old.

Individual cats still age at different rates depending on breed, lifestyle and overall health. This is an age-equivalence reference, not a medical measurement.

Cat Life Stages

International Cat Care divides a cat's life into six stages. The calculator above uses exactly the same boundaries, so the life stage it shows always matches this list.

Kitten

Birth – 6 months

A period of rapid growth, when kittens learn about the world and develop social skills.

Junior

7 months – 2 years

Much like the teenage years in people — cats reach full size and become increasingly independent.

Adult

3 – 6 years

Cats are physically and behaviourally mature, and typically at their most active.

Mature

7 – 10 years

Equivalent to humans in their mid-40s to mid-50s; cats often start to slow down a little.

Senior

11 – 14 years

Cats are usually less active and may appreciate easier access to their favourite spots.

Super Senior

15+ years

Many cats reach this stage; subtle changes in behaviour are worth keeping an eye on.

Frequently Asked Questions

How old is my cat in human years?

A one-year-old cat is roughly 15 in human years, and a two-year-old cat about 24. After that, each additional cat year adds around four human years. Enter your cat's age in the calculator above to get the exact equivalent for any age from birth to 25 years.

How do cat years compare with human years?

Cats mature far faster than humans in their early life: the first cat year is roughly equivalent to 15 human years and the second to about nine more, bringing a two-year-old cat to roughly 24 human years. From age three onwards, each cat year is approximately four human years. This is an age-equivalence reference, not a medical measurement.

Is a 7-year-old cat old?

A 7-year-old cat enters the Mature life stage in the age system used by this calculator, equivalent to roughly 44 human years. Mature cats are often still active and healthy — the Senior stage does not begin until 11 years.

When is a cat considered senior?

In the age system used by this calculator, a cat is considered Senior from 11 years old (the Senior stage covers 11–14 years). From 15 years onwards, cats are classed as Super Senior.

How accurate are cat age calculators?

Cat age calculators give an evidence-based estimate, not an exact figure. This calculator follows International Cat Care age guidance, which reflects how cats typically mature. Individual cats age at different rates depending on breed, lifestyle and overall health, so treat the result as an age-equivalence reference rather than a medical measurement.

Related Guides

Sources

Primary source for the calculator, age chart and life stages:

Last reviewed: August 2026

This page is evidence-based and follows International Cat Care age guidance.

This page is for general information only and is not a substitute for veterinary advice. If you are worried about your cat, contact your vet.