Cat Age Calculator
Convert your cat’s age to human years and see its life stage.
Not sure of the exact age? Your vet can estimate it from teeth, eyes and coat.
In human years
56 human years
- Life stage
- Mature adult
- Vet checkups
- At least once a year
How: 24 + 4 × (10 − 2) = 56.0.
Quick answer
A cat’s first year equals about 15 human years and its second about 24. After that, each cat year adds about 4 human years. So a 5-year-old cat is about 36, a 10-year-old about 56, and a 15-year-old about 76. Cats over 10 are seniors.
How do I use the cat age calculator?
- Enter your cat’s age in years and months. For a rescue cat, use your vet’s best estimate.
- Read the human-equivalent age and life stage.
- Check how often your vet recommends checkups at that stage.
What formula does the cat age calculator use?
After 2: human age = 24 + 4 × (cat age − 2)
Under 1 year: 1 month ≈ 1, 3 months ≈ 4, 6 months ≈ 10 (straight lines in between)
These numbers are the chart published by the American Association of Feline Practitioners alongside the 2021 AAHA/AAFP Feline Life Stage Guidelines. Unlike dogs, cats don’t vary much in size, so one chart fits almost all cats. The life stages are from the same guidelines: kitten (birth to 1 year), young adult (1–6), mature adult (7–10) and senior (over 10).
How is the calculation done?
For the default example, a 10-year-old cat:
- The first year counts as about 15 human years.
- The second year adds about 9 more: 24 at age 2.
- Each year after that adds about 4: 10 − 2 = 8 more years × 4 = 32.
- Total: 24 + 32 = 56 human years.
- Life stage: 10 years is mature adult (7–10 years). After 10, cats count as seniors.
Worked example: a 6-month-old kitten and a 17-year-old cat
A 6-month-old kitten is about 10 in human years: think of a child in primary school, with a lot of growing still to do. A 17-year-old cat is 24 + 4 × 15 = 84. That’s a very senior cat, and vets suggest checkups every six months at that age.
Cat age chart: cat years to human years
| Cat age | Human years | Life stage |
|---|---|---|
| 1 month | 1 | Kitten |
| 3 months | 4 | Kitten |
| 6 months | 10 | Kitten |
| 1 year | 15 | Young adult |
| 2 years | 24 | Young adult |
| 3 years | 28 | Young adult |
| 4 years | 32 | Young adult |
| 5 years | 36 | Young adult |
| 6 years | 40 | Young adult |
| 7 years | 44 | Mature adult |
| 8 years | 48 | Mature adult |
| 9 years | 52 | Mature adult |
| 10 years | 56 | Mature adult |
| 11 years | 60 | Senior |
| 12 years | 64 | Senior |
| 13 years | 68 | Senior |
| 14 years | 72 | Senior |
| 15 years | 76 | Senior |
| 16 years | 80 | Senior |
| 17 years | 84 | Senior |
| 18 years | 88 | Senior |
| 19 years | 92 | Senior |
| 20 years | 96 | Senior |
| 21 years | 100 | Senior |
| 22 years | 104 | Senior |
| 23 years | 108 | Senior |
| 24 years | 112 | Senior |
| 25 years | 116 | Senior |
What do the cat life stages mean for care?
- Kitten (0–1): vaccines, parasite control, spay/neuter, and kitten food with about 2.5 times adult resting calories.
- Young adult (1–6): yearly checkups, dental care, and keeping weight in check, since this is when many cats get heavy.
- Mature adult (7–10): yearly checkups; ask about blood tests to spot kidney or thyroid changes early.
- Senior (over 10): checkups about every 6 months, watching weight, thirst, litter box habits and mobility.
When should you see your vet?
- Your cat loses weight, drinks or pees more, or changes litter box habits.
- Your cat hides more, stops grooming, or stops jumping up to favorite spots.
- Your cat stops eating for more than a day. In cats this can quickly become serious.
Frequently asked questions
How old is my cat in human years?
A 1-year-old cat is about 15, a 2-year-old about 24, and then add about 4 years for each year after that. So a 10-year-old cat is roughly 56.
When is a cat a senior?
The AAFP/AAHA feline life stage guidelines call cats over 10 years senior. Mature adults are 7–10, young adults 1–6, and kittens are under 1 year.
Do indoor cats age differently?
The conversion is the same, but indoor cats tend to live longer on average because they face fewer accidents, fights and infections.
How often should an older cat see the vet?
The guidelines recommend at least yearly exams for all cats, and the AAFP life stage chart suggests every 6 months for seniors. Cats hide illness well, so regular checks catch problems earlier.
Is 1 cat year really 7 human years?
No. Cats grow up very fast in the first two years: a 1-year-old cat is roughly like a 15-year-old person. After that, each cat year is about 4 human years, not 7.
How long do cats live?
Many pet cats live into their mid-teens, and plenty reach 20. Indoor life, a healthy weight and regular vet care all help. The chart goes up to 25 cat years, which is about 116 in human years.
Sources
- American Association of Feline Practitioners. Feline Life Stages: cat age to human age chart (2021). catfriendly.com
- Quimby J, et al. 2021 AAHA/AAFP Feline Life Stage Guidelines. J Feline Med Surg 2021;23(3):211–233. doi.org
- AAHA / Zoetis. “My pet’s physiological age” poster (cat chart adapted from AAFP-AAHA Feline Life Stage Guidelines). aaha.org
Vet disclaimer: These are estimates for healthy pets. Your vet knows your pet. Ask them before changing diet or care, especially for puppies, kittens, seniors, pregnant pets or pets with health conditions. Read our medical disclaimer.