Cat Age Calculator

Convert your cat’s age to human years with the standard feline chart and see its life stage. Calculates in your browser.

Roughly equivalent human age

-

Life stage-

Show the math

Cats grow up quickly and then age steadily. The human ages come from the feline age chart in the AAFP–AAHA Feline Life Stage Guidelines: 1 month ≈ 1, 3 months ≈ 4, 6 months ≈ 10, 12 months ≈ 15, 18 months ≈ 21 and 2 years ≈ 24 human years. Ages between those points are read along a straight line, then every cat year after two adds 4 human years:

human = 24 + (years − 2) × 4

So a 6-month-old kitten is about 10, a 2-year-old about 24, and a 10-year-old around 56.

Life stages follow the 2021 AAHA/AAFP Feline Life Stage Guidelines: kitten (birth up to 1 year), young adult (1–6 years), mature adult (7–10 years) and senior (over 10 years).

These are averages, indoor cats often live well into their late teens. Everything is calculated in your browser.

What this does

A cat age calculator converts your cat’s age to human years with the standard feline chart and shows its life stage.

How to use it

  1. Enter your cat’s age.
  2. Choose years or months.
  3. Read the human-year equivalent.
  4. See the life stage.

How it works

Under two years the human age is read from the feline age chart in the AAFP–AAHA Feline Life Stage Guidelines, between its monthly points so part-years never jump; each year after two adds 4 human years. Life stages follow the 2021 AAHA/AAFP Feline Life Stage Guidelines. Many indoor cats live well into their late teens.

chart to 2 years (6 months ≈ 10, 1 year ≈ 15, 18 months ≈ 21, 2 years ≈ 24), then +4 per year

Understanding your result

The human-age figure mainly tells you your cat’s life stage, which guides diet, activity, and vet care. The first two years account for most of the aging, then it settles to about four human years annually, and many indoor cats stay healthy well into their late teens.

Example

A 3-year-old cat is about 28 in human years.

Last updated .

Frequently asked questions

How are cat years calculated?

The first year counts as about 15 human years (a 6-month-old kitten is about 10), the second adds 9 more to reach 24, and every year after that adds roughly 4 human years.

When is a cat a senior?

The 2021 AAHA/AAFP Feline Life Stage Guidelines call a cat a kitten from birth up to 1 year, a young adult from 1 through 6 years, a mature adult from 7 to 10 years, and a senior when over 10 years. An end-of-life stage can come at any age.

Is anything stored?

No. Everything is calculated locally in your browser.