Cat age calculator
How old your cat is in human years.
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This tool runs entirely in your browser. What you paste is processed on your device and is never sent to a server, so it is safe to use with tokens, keys and unpublished text.
Example
Example: three cats in one home — a kitten, a rescue of about 2½ and a 14-year-old
A family has three cats: Pepper, 4 months; Biscuit, a rescue the shelter thinks is about 2 years 6 months; and Smokey, who is 14. Each age is typed as years, with the months picked from the list, and Show the chart left on.
- Pepper, 0 years 4 months: about 6 in human years, Kitten (0–6 months). The first year follows the kitten points — 1 month ≈ 1, 3 ≈ 4, 6 ≈ 10, 12 = 15 — in a straight line between them.
- Biscuit, 2 years 6 months: about 26, Junior. Junior runs from 7 months up to the third birthday; Prime starts at 3.
- Smokey, 14 years: about 72, Senior (11–14 years), marked with an arrow in the chart. At 15 the line reads 76 and Geriatric.
- From the second birthday on, each year adds 4 — 2 is 24, 3 is 28, 10 is 56 — and half a year adds 2, so 10 years 6 months is 58.
| Cat’s age | In human years | Life stage |
|---|---|---|
| 4 months | 6 | Kitten |
| 9 months | 13 | Junior |
| 1 year 6 months | 20 | Junior |
| 2 years 6 months | 26 | Junior |
| 7 years | 44 | Mature |
| 10 years 6 months | 58 | Mature |
| 14 years | 72 | Senior |
| 15 years | 76 | Geriatric |
| 18 years | 88 | Geriatric |
Three cats, three stages. The life stage is the useful part — a guide to care, food and check-ups — while the human age is an average: breed, weight and health change how each cat ages.
How it works
- Type your cat’s age in years and months (months alone for a kitten).
- Read its age in human years and its life stage.
- Look at the chart for every age from 1 to 20.
Frequently asked questions
- How do you convert cat years to human years?
- A cat’s first year is about 15 human years and the second brings it to 24; after that each year counts for about 4 human years. A 10-year-old cat is about 56.
- What are a cat’s life stages?
- Kitten up to 6 months, junior to 2 years, prime 3–6, mature 7–10, senior 11–14 and geriatric from 15. The stage is a guide to care, food and check-ups.
- How long do cats live?
- Indoor cats often live 12–18 years and many reach their twenties. Care, weight and regular check-ups matter more than any chart.
- Is it the same for every breed?
- The chart is an average; breeds and individual cats age a little differently, so read it as an estimate.
- How is a kitten’s age in months converted?
- With the points of the usual chart — 1 month is about 1 human year, 3 months about 4, 6 months about 10 and 12 months 15 — and a straight line between them. So a 4-month-old kitten is about 6 and a 9-month-old about 13.
- Does it work for a cat over 20?
- Yes. Ages up to 30 years can be typed; the chart stops at 20, the answer does not. A 21-year-old cat is about 100 in human years, and every year after the second still adds 4.
- Is anything sent anywhere?
- No. It is worked out in your browser.
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