Cat age chart · Quick conversion

Cat Years to Human Years

Use the table below to compare a cat's calendar age with an estimated human equivalent and a general feline life stage. It covers every month through 24 months, then each year through age 20.

Need an exact result for a specific month? Use the Cat Age Calculator. It uses the same 15 / 24 / +4 model and adds life-stage context.

Conversion table

Cat years to human years conversion chart

Values are estimates from the same model used by the Cat Age Calculator. The life-stage labels follow the 2021 AAHA/AAFP feline life-stage bands, with boundaries made explicit for a month-based chart.

Cat years to human years conversion table from 0 months to 20 years
Cat age	Estimated human age	Life stage
0 months	0 human years	Kitten
1 month	1.3 human years	Kitten
2 months	2.5 human years	Kitten
3 months	3.8 human years	Kitten
4 months	5 human years	Kitten
5 months	6.3 human years	Kitten
6 months	7.5 human years	Kitten
7 months	8.8 human years	Kitten
8 months	10 human years	Kitten
9 months	11.3 human years	Kitten
10 months	12.5 human years	Kitten
11 months	13.8 human years	Kitten
12 months	15 human years	Young Adult
13 months	15.8 human years	Young Adult
14 months	16.5 human years	Young Adult
15 months	17.3 human years	Young Adult
16 months	18 human years	Young Adult
17 months	18.8 human years	Young Adult
18 months	19.5 human years	Young Adult
19 months	20.3 human years	Young Adult
20 months	21 human years	Young Adult
21 months	21.8 human years	Young Adult
22 months	22.5 human years	Young Adult
23 months	23.3 human years	Young Adult
24 months	24 human years	Young Adult
3 years	28 human years	Young Adult
4 years	32 human years	Young Adult
5 years	36 human years	Young Adult
6 years	40 human years	Young Adult
7 years	44 human years	Mature Adult
8 years	48 human years	Mature Adult
9 years	52 human years	Mature Adult
10 years	56 human years	Mature Adult
11 years	60 human years	Senior
12 years	64 human years	Senior
13 years	68 human years	Senior
14 years	72 human years	Senior
15 years	76 human years	Senior
16 years	80 human years	Senior
17 years	84 human years	Senior
18 years	88 human years	Senior
19 years	92 human years	Senior
20 years	96 human years	Senior

Values are rounded to one decimal place. They are educational estimates, not a measure of a cat's actual biological age.

How to read the chart

Three anchors explain the conversion

At 1 year

About 15 human years. The first year contains the fastest development.

At 2 years

About 24 human years. The second year adds the next nine human-year equivalents.

After 2 years

Add about four human years for each additional calendar year on this model.

Formula and boundaries

What this chart does and does not measure

Human-age estimate

The 15 / 24 / +4 rule is a transparent educational approximation: 15 human years at one calendar year, 24 at two, then about four more for each year after that. Month rows are interpolated between the anchors.

Life-stage label

AAHA/AAFP guidance describes Kitten as under 1 year, Young adult as 1–6 years, Mature adult as 7–10 years, and Senior as over 10 years. This table turns those bands into non-overlapping month boundaries.

Individual health

A calendar conversion cannot diagnose health or predict lifespan. Breed, genetics, nutrition, body condition and veterinary care all affect an individual cat.

For a result that accepts a specific age and month, continue to the Cat Age Calculator. It shares this page's conversion function, so the two pages stay consistent.

Questions people ask

Cat years to human years FAQ

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

A 1-year-old cat is about 15 human years on the educational model used in this chart. The first calendar year is a rapid development period, so it is not equivalent to seven human years.

How old is a 2-year-old cat in human years?

A 2-year-old cat is about 24 human years. After the second year, the chart adds about four human years for each additional calendar year.

Do cats age seven years for every calendar year?

No. The seven-year rule is a rough shortcut. Cats mature quickly during their first two years and then age more gradually on this 15 / 24 / +4 approximation.

Is this cat age chart medically accurate?

It is an educational estimate, not a biological age measurement or a medical test. Breed, health, genetics and lifestyle can affect an individual cat differently.

How are cat months converted to human years?

The chart interpolates between the model's anchors: 15 human years at 12 months and 24 at 24 months. That keeps month-level rows consistent with the Cat Age Calculator.

Sources and model notes

The life-stage labels use the veterinary guideline below. The 15 / 24 / +4 conversion is presented as a commonly used educational convention; it is not a formula published by the guideline or by a lifespan study.

2021 AAHA/AAFP Feline Life Stage Guidelines · PMC full text
Supports the four feline life-stage bands used for the third column.
Cat Age Calculator formula notes
Shows the same model boundary and explains why human-age equivalents are estimates.

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