How to use it
- Enter your cat's age in years and months.
- Read the age in human years.
- Check the life stage and the finer age group.
- Open the cat years chart for a quick reference.
How cat years work
Cats grow up fast. By their first birthday they are roughly the equivalent of a 15-year-old, and by two, about 24. After that, each cat year counts as roughly four human years. The calculator follows the age-equivalence chart in the 2010 AAFP–AAHA Feline Life Stage Guidelines:
| Cat age | Human years |
|---|---|
| 1 month | 1 |
| 3 months | 2–4 |
| 6 months | 10 |
| 1 year | 15 |
| 2 years | 24 |
| 5 years | 36 |
| 10 years | 56 |
| 15 years | 76 |
| 20 years | 96 |
For young kittens, where the chart gives a range, the result shows the range. Between chart points the value is interpolated, so months count too.
Quick formula
If you want to work it out yourself for a cat older than two:
human years ≈ 24 + 4 × (cat age − 2)
So a 7-year-old cat is about 24 + 4 × 5 = 44, and a 14-year-old about 24 + 4 × 12 = 72. For cats under two, use the chart: the first year counts as about 15 human years and the second as about 9 more.
The popular "multiply by seven" rule doesn't work well for cats either: it makes a 1-year-old cat 7 instead of a mature-looking 15, and a 20-year-old cat 140 instead of about 96.
Life stages
The calculator also tells you your cat's life stage, using the 2021 AAHA/AAFP Feline Life Stage Guidelines:
| Stage | Age |
|---|---|
| Kitten | birth to 1 year |
| Young adult | 1–6 years |
| Mature adult | 7–10 years |
| Senior | over 10 years |
A colored bar shows where your cat sits on that timeline. For comparison, the older 2010 guideline's finer groups are also shown: kitten (0–6 months), junior (7 months–2 years), prime (3–6 years), mature (7–10 years), senior (11–14 years) and geriatric (15+ years).
Why life stage matters
The stage is more useful than the human-years number. Veterinary guidelines tailor care to it:
- Kittens: vaccinations, parasite control, spaying or neutering, and socialization.
- Young adults: weight control and routine checkups; many indoor cats start gaining weight in this period.
- Mature adults: watch for dental disease and weight changes.
- Seniors: more frequent exams are often recommended, since kidney disease, thyroid problems, arthritis and diabetes become more common. Cats hide pain well, so changes in appetite, litter box habits, grooming or jumping deserve a vet visit.
Many indoor cats live into their mid-to-late teens, and some reach 20 or more. The calculator handles ages up to 30 years.
Indoor and outdoor cats
The age conversion is the same for every cat, but lifestyle affects how long cats live. Indoor cats are protected from traffic, fights and many infections, and generally live longer than cats that roam outdoors. Keeping your cat at a healthy weight, up to date on preventive care and seen by a vet regularly matters at every stage.
Limitations
Human-year equivalents are an illustration, not a medical age. Individual cats vary with genetics, breed, weight, environment and health. Treat the result as a conversation starter, and ask your veterinarian about the care your cat needs at its stage.
The calculation runs in your browser. For dogs, try the dog age calculator, which takes size into account.
Frequently asked questions
How old is my cat in human years?
Enter your cat's age. A 1-year-old cat is about 15 human years, a 2-year-old about 24, and each year after that adds about 4.
How old is a 10-year-old cat in human years?
About 56 human years.
At what age is a cat a senior?
The 2021 AAHA/AAFP guidelines consider cats seniors after 10 years of age.
Is one cat year equal to seven human years?
No. Cats age much faster in their first two years, then about four human years per cat year.
Is this medical advice?
No. It's an illustration based on veterinary guidelines; your vet can judge your cat's actual health.
Last updated: November 12, 2026