What is the Cat Age Calculator?
A cat ages quickly in its first two years and more slowly after that. This calculator converts your cat's age into the human equivalent using the widely used scale.
How to use the Cat Age tool
- Enter Cat age.
- The result updates instantly as you type, or press Calculate.
- Use Try an example to see how it works, and Reset to start again.
Formula
Year 1 ≈ 15 human years. Year 2 adds 9 (total 24). Each further year adds about 4.
Worked example
A 5-year-old cat is about 24 + 3 × 4 = 36 human years old, an adult.
Frequently asked questions
How old is a 1-year-old cat in human years?
About 15 human years.
How long do cats live?
Indoor cats often live 12 to 18 years.
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Checked by Calcovate · Formula tested against worked examples · Updated 7 Nov 2026 · How we check our calculators.