Cat Age Calculator — Cat Years to Human Years

Convert your cat's age into human years with the vet-recognised feline aging formula. 🐈

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Cat Age Calculator

Cat years → human years

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Enter your cat's age to see human years

How to Use the Cat Age Calculator

  1. Enter your cat's age in years (use decimals like 0.5 for 6 months).
  2. Choose indoor or outdoor — outdoor cats face more wear and tear.
  3. Tap calculate to see the human-equivalent age and life stage.

Why It's Accurate

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Vet formula

First year ≈ 15 human years, second ≈ 9 more, then about 4 per year — the standard feline aging model.

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Life stage

Kitten, adult, mature or senior — so you can match care and diet to their stage.

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Instant & private

Calculated in your browser, nothing stored.

How Cat Years Work

Cats mature very quickly in their first two years and then settle into a steadier pace. The accepted model counts the first year as roughly 15 human years, the second as about 9 more (so a 2-year-old cat ≈ 24 in human terms), and then about 4 human years for every additional cat year. By that math a 10-year-old cat is around 56 in human years.

Indoor cats generally live longer and age a little more gently than outdoor cats, who face more hazards. This tool uses the standard formula with a small lifestyle adjustment so you get a realistic picture of where your cat is in life.

Cat Age FAQ

About 24 human years. The first year counts as ~15 and the second adds ~9 more.
Cats are usually considered senior around 11 years (about 60 in human years) and "geriatric" from about 15.
Generally yes — indoor cats avoid traffic, predators and many diseases, so they often live several years longer than outdoor cats.

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✔ Reviewed by the True Value Calc editorial team🗓 Last updated June 2026📚 Sources: Peer-reviewed formulas & official U.S. government data