Cat Age Calculator
Cat Age Calculator works out Human-equivalent age and Age used from Age in years, Extra months and Date of birth. The default figures on this page give human-equivalent age of 36.0 years; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
6 steps
- Age used: 5 cat years (age entered directly).
- First two years = 15 + 9 = 24 human years.
- Each year after the second is worth 4 human years for a cat: 4 x 3 = 12.
- Total = 24 + 12 = 36 human years.
- At this age the animal gains about 4 human years per pet year.
- Human-equivalent 65 is reached at about 12.25 cat years.
Age conversion charttable
| petYears | humanYears |
|---|---|
| 1 | 15 |
| 2 | 24 |
| 3 | 28 |
| 4 | 32 |
| 5 | 36 |
| 6 | 40 |
| 7 | 44 |
| 8 | 48 |
| 9 | 52 |
| 10 | 56 |
| 11 | 60 |
| 12 | 64 |
| 13 | 68 |
| 14 | 72 |
| 15 | 76 |
| 16 | 80 |
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
What the Cat Age Calculator calculates
Converts a dog or cat’s age into human-equivalent years using the AVMA/AAHA staged model by size, or the Wang (2020) canine epigenetic clock, and reports the life stage that age falls into.
How to use this Cat Age Calculator
Enter Age in years, Extra months, Date of birth and Age as of. Human-equivalent age updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Human-equivalent age, Age used and Age in months.
The method follows American Veterinary Medical Association, "How old is my pet in human years?" guideline as published in the AKC dog-age conversion chart, International Cat Care / AAFP / AAHA feline life-stage age conversion and Wang T, Ma J, Hogan AN, et al. Quantitative Translation of Dog-to-Human Aging by Conserved Remodeling of the DNA Methylome. Cell Systems 11(2):176-185 (2020).
What you can compare
Change one input at a time to see how it affects Human-equivalent age, Age used and Age in months. The inputs you can vary are Age in years, Extra months, Date of birth, Age as of and Conversion model.
Understanding Human-equivalent age, Age used and Age in months
Age conversion is a rough population guide, not a health assessment. Life stage, senior screening and any change in care should be decided by a veterinarian who has examined the animal.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
How do I calculate a cat's age?
Converts a dog or cat’s age into human-equivalent years using the AVMA/AAHA staged model by size, or the Wang (2020) canine epigenetic clock, and reports the life stage that age falls into. Open “How this is worked out” beside the result to see each step for your own figures.
How can I tell how old my cat is?
It needs Age in years, Extra months, Date of birth, Age as of and Conversion model. Nothing else is required, and the figures stay in your browser.
How old is a 12 year old cat in cat years?
The result gives Human-equivalent age, Age used, Age in months, Life stage of the human-equivalent age, Human years gained per pet year now and Reaches human-equivalent 65 at, each labelled with its unit so the figure can be read on its own.
Is there a cat age chart?
Converts a dog or cat’s age into human-equivalent years using the AVMA/AAHA staged model by size, or the Wang (2020) canine epigenetic clock, and reports the life stage that age falls into. On the figures this page opens with — age in years 7 — the human-equivalent age is 36 years. Put your own figures in their place and the working updates beside the result.
What information do I need for the Cat Age Calculator?
You need Age in years, Extra months, Date of birth, Age as of and Conversion model. The page opens with default figures that give human-equivalent age of 36.0 years, so you can see the scale before entering your own.
What does this Cat Age Calculator show?
It shows Human-equivalent age, Age used, Age in months, Life stage of the human-equivalent age, Human years gained per pet year now, Reaches human-equivalent 65 at, Model used and Size band used, with the working and any warnings for your entries.