Cat Years to Human Years Calculator
A cat’s first year equals about 15 human years and its second about 9 more (24 at age 2). After that, each cat year is about 4 human years, so a 10-year-old cat is about 56 and a 15-year-old about 76.
Kittens age fastest: a 6-month-old kitten is already about 10 in human years.
How it works
We use the International Cat Care chart. For kittens it goes month by month (2 months ≈ 2 years, 3 months ≈ 4, 6 months ≈ 10, 7 months ≈ 12, 12 months ≈ 15, 18 months ≈ 21, 2 years ≈ 24). After 2 years:
human age = 24 + 4 × (cat age in years − 2)
Between chart rows we interpolate in a straight line. The chart runs to 25 years (116 human years).
How to use it
- Enter your cat’s age. Years and months, or pick the birthday.
- Read the human age. We use the International Cat Care chart and fill in between rows.
- Check the life stage. Both the AAHA/AAFP and International Cat Care stages are shown.
Cat years to human years chart
| Cat age | Human years |
|---|---|
| 0–1 month | 0–1 |
| 2 months | 2 |
| 3 months | 4 |
| 4 months | 6 |
| 5 months | 8 |
| 6 months | 10 |
| 7 months | 12 |
| 12 months | 15 |
| 18 months | 21 |
| 2 years | 24 |
| 3 years | 28 |
| 4 years | 32 |
| 5 years | 36 |
| 6 years | 40 |
| 7 years | 44 |
| 8 years | 48 |
| 9 years | 52 |
| 10 years | 56 |
| 11 years | 60 |
| 12 years | 64 |
| 13 years | 68 |
| 14 years | 72 |
| 15 years | 76 |
| 16 years | 80 |
| 17 years | 84 |
| 18 years | 88 |
| 19 years | 92 |
| 20 years | 96 |
| 21 years | 100 |
| 22 years | 104 |
| 23 years | 108 |
| 24 years | 112 |
| 25 years | 116 |
Source: International Cat Care.
Frequently asked questions
How old is my cat in human years?
1 year ≈ 15, 2 years ≈ 24, then add 4 for each year. A 10-year-old cat is about 56, a 15-year-old about 76 and a 20-year-old about 96 (International Cat Care).
Is one cat year seven human years?
No. Cats grow up very fast: by 1 year a cat is about 15 in human terms and by 2 about 24. After that each year is about 4 human years.
When is a cat a senior?
The 2021 AAHA/AAFP guidelines call cats over 10 years senior. International Cat Care uses senior for 11–14 years and super senior for 15 years and over.
How long do cats live?
International Cat Care says cats live on average for around 12–14 years, and it is not unusual for some to reach their late teens or early twenties.
When to see a vet
- Your cat is over 10: ask about senior check-ups.
- Weight loss, drinking more, changes in litter-box habits, or hiding more than usual.
- Your cat has stopped eating for more than a day.
This is an estimate for general information, not veterinary advice. Every pet is different. Ask your veterinarian before changing your pet's diet, especially for puppies, kittens, pregnant or nursing pets, seniors, or pets with health conditions.
Sources
- International Cat Care. How to tell your cat’s age in human years (cat age chart). icatcare.org/articles/how-to-tell-your-cats-age-in-human-years
- Quimby J, Gowland S, Carney HC, et al. 2021 AAHA/AAFP Feline Life Stage Guidelines. J Feline Med Surg. 2021;23(3):211–233. doi.org/10.1177/1098612X21993657
- AAHA. 2021 AAHA/AAFP Feline Life Stage Guidelines: Feline life stage definitions. www.aaha.org/resources/2021-aaha-aafp-feline-life-stage-guidelines/feline-life-stage-definitions/
Full methodology: sources and methodology. Last reviewed 20 October 2026.