Cat age calculator: cat years to human years
Is your cat a teenager, a grown-up, or the wise one in the house? Enter an age or birthday for a human-age estimate, then save or share their result.
Cat years to human years chart
| Cat age | Human-age estimate |
|---|---|
| 6 months | 10 |
| 1 year | 15 |
| 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 |
These are PetAgeNow estimates, rounded to whole human years. Months between table entries are interpolated. The same calculation powers the chart and calculator.
How to calculate cat years
For cats aged 2 years or more, our formula is 24 + 4 × (cat age − 2). For example, an 8-year-old cat is 24 + 4 × 6 = 48 human years. Younger cats use table points at 6 months, 1 year, and 2 years instead of the adult formula.
Why multiplying by seven gives a different answer
A single multiplier cannot capture the fast early development shown by this age model. Multiplying a 2-year-old cat’s age by seven gives 14; our table gives 24. Human years are a comparison to help put an age in perspective, rather than a measurement of biological age.
Human age and life stage answer different questions
The AAHA / AAFP guidelines group cats as kittens under 1 year, young adults from 1–6, mature adults from 7–10, and seniors over 10. Our calculator’s descriptive labels use a different set of age bands. Neither a human-age number nor a label replaces an assessment of your individual cat.
If you do not know your cat’s birthday
Use the age estimate on adoption or veterinary records and choose Enter age. You can edit the result later. A guessed birthday does not make the calculation more precise; entering an estimated age is fine.
Common questions
How old is a 10-year-old cat in human years?
PetAgeNow estimates 56 human years: 24 for the first two years, then 8 × 4 for the next eight.
How old is a 15-year-old cat in human years?
Our age table gives about 76 human years. This comparison does not predict how long a cat will live.
Do indoor and outdoor cats use different formulas?
This calculator uses one cat age table and does not adjust for indoor or outdoor living. Lifestyle and health matter to an individual cat, but they are not measured by this tool.
Can I calculate an age in months?
Yes. Enter years and months, or choose Enter birthday. For a 6-month-old kitten, enter 0 years and 6 months. Our model estimates about 10 human years.
Sources and calculation notes
Written by PetAgeNow. Numbers come from our own calculator tables. Veterinary resources provide life-stage context and do not endorse or validate this calculator.
Age comparisons are educational estimates. They do not predict health, behavior, or lifespan.