Cat age calculator: cat years to human years

Enter your cat’s age in years and months. The calculator shows the equivalent human age from the chart published by the American Association of Feline Practitioners (AAFP) and AAHA, plus the life stage your cat is in right now.

How it is calculated

How cat years convert to human years

The “one cat year equals seven human years” rule is wrong: cats grow up very quickly in their first year and age more slowly afterwards. This calculator uses the conversion chart from the AAFP-AAHA Feline Life Stage Guidelines (2010):

First year: 12 months ≈ 15 human years (6 months ≈ 10, 7 months ≈ 12)
Second year: 18 months ≈ 21, 2 years ≈ 24 human years
after that, +4 human years for every cat year

Formula from age 2: human years = 24 + (cat age − 2) × 4. Example: a 10-year-old cat equals 24 + 8 × 4 = 56 human years. Ages between chart points (e.g. 9 months) are interpolated linearly and rounded to whole years.

Cat age	Human age
1 month	1 year
2–3 months	2–4 years
4 months	6–8 years
6 months	10 years
1 year	15 years
2 years	24 years
5 years	36 years
10 years	56 years
15 years	76 years
20 years	96 years
25 years	116 years

Cat life stages

The current 2021 AAHA/AAFP Feline Life Stage Guidelines divide a cat’s life into four age-related stages: kitten (birth up to 1 year), young adult (1–6 years), mature adult (7–10 years) and senior (over 10 years), plus an end-of-life stage that is not tied to a specific age. The calculator assigns stages by completed years, so a cat counts as senior from its 11th birthday.

Limits of the conversion

A human-age figure is an illustration, not a medical finding. Cats age individually – breed, lifestyle, weight and illness all play a part, and the guidelines recommend reassessing the life stage at every exam. This calculator does not replace advice from your veterinarian.

Frequently asked questions

How old is a 1-year-old cat in human years?

About 15. In its first year a cat passes through childhood and puberty; at 2 years it is roughly like a 24-year-old person.

Is the “multiply by 7” rule correct?

No. Under the AAFP-AAHA chart the first two years add up to about 24 human years and every year after that to about 4. A 10-year-old cat is therefore about 56, not 70.

At what age is a cat a senior?

According to the 2021 AAHA/AAFP guidelines, cats over 10 years are seniors. From 7 to 10 years they are mature adults.

How often should an older cat see the vet?

The guidelines recommend at least one exam a year for all cats and at least every 6 months for senior cats – more often with chronic conditions.

How old is a 20-year-old cat in human years?

About 96: 24 + (20 − 2) × 4 = 96.

Sources and legal basis

doi:10.1177/1098612X21993657: Quimby J, Gowland S, Carney HC et al.: 2021 AAHA/AAFP Feline Life Stage Guidelines. J Feline Med Surg 2021;23(3):211–233 (Table 1: life stages)
doi:10.1016/j.jfms.2009.12.006: Hoyumpa Vogt A, Rodan I, Brown M et al.: AAFP-AAHA Feline Life Stage Guidelines. J Feline Med Surg 2010;12(1):43–54 (box “Life stages in cats”, human equivalent)
American Association of Feline Practitioners (AAFP) – AAHA/AAFP Feline Life Stage Guidelines

As of: 27 September 2026