A cat's first year equals about 15 human years, its second year about 9 more, and every year after that about 4. So a 3-year-old cat is about 28 in human years, and a 10-year-old cat about 56.
These are the equivalents in the feline life-stage guidelines published by the American Animal Hospital Association and the American Association of Feline Practitioners. The calculator also tells you your cat's life stage and what it means for care.
Worked example
Cat's age: 3 years
At 3 years old, your cat is about: 28 in human years
15 human years for the first year, 9 for the second and 4 for the third make 28 — a young adult cat.
Open this example in the calculator →How to use the Cat Age Calculator
- Enter your cat's age in years, and months for a kitten.
- Read your cat's age in human years.
- Check its life stage — kitten, young adult, mature adult or senior.
- Compare other ages in the chart below.
Cat years to human years
Cats grow up fast. By 6 months a kitten is roughly a 10-year-old child, by its first birthday it is like a 15-year-old, and by two it is a young adult of about 24. From then on, each cat year is worth about four human years.
| Cat age | Human years | Cat age | Human years |
|---|---|---|---|
| 1 | 15 | 11 | 60 |
| 2 | 24 | 12 | 64 |
| 3 | 28 | 13 | 68 |
| 4 | 32 | 14 | 72 |
| 5 | 36 | 15 | 76 |
| 6 | 40 | 16 | 80 |
| 7 | 44 | 17 | 84 |
| 8 | 48 | 18 | 88 |
| 9 | 52 | 19 | 92 |
| 10 | 56 | 20 | 96 |
Cat life stages
The 2021 AAHA/AAFP Feline Life Stage Guidelines describe four stages:
- Kitten — birth to 1 year.
- Young adult — 1 to 6 years.
- Mature adult — 7 to 10 years.
- Senior — over 10 years. The guidelines recommend a veterinary visit at least every 6 months from here.
Many cats live well into their teens. Indoor cats commonly reach 12 to 18 years, and some live past 20.
Why not multiply by 7?
Like the dog rule, "seven cat years for every human year" is just an average. It badly underestimates young cats — a 1-year-old cat is physically an adolescent, not a 7-year-old — and it slightly overstates the age of old ones.
Frequently asked questions
How old is my cat in human years?
Count 15 for the first year, 9 for the second, and 4 for every year after that. A 3-year-old cat is about 28, a 10-year-old about 56 and a 15-year-old about 76.
How old is a 1-year-old cat in human years?
About 15 — a teenager. A 6-month-old kitten is roughly 10.
When is a cat a senior?
Over 10 years old, in the 2021 AAHA/AAFP guidelines. Senior cats should see the vet at least every 6 months.
Is a cat year seven human years?
No. Cats mature much faster than that in their first two years, then age about four human years for each year.
How long do cats live?
Indoor cats commonly live 12 to 18 years, and some reach 20 or more. A 20-year-old cat is about 96 in human years.