Cat Age in Human Years Calculator
Convert your cat's age to the equivalent human age using the internationally recognised AAFP/ISFM feline life-stage guide.
How to use this tool
- Enter your cat's age in years (decimals ok for kittens).
- The calculator shows the human-equivalent age and life stage.
- Use the life stage to understand your cat's care needs.
Find out your cat's equivalent human age and life stage using the AAFP/ISFM feline ageing scale, the standard used by veterinarians worldwide.
Not veterinary advice. These results are estimates for general guidance only. Always consult a licensed veterinarian before making health, nutrition, or medication decisions for your pet.
Formula
Age ≤ 1 yr: human = cat_age × 15
1–2 yr: human = 15 + (cat_age − 1) × 9
2–6 yr (Prime): human = 24 + (cat_age − 2) × 4
6–10 yr (Mature): human = 40 + (cat_age − 6) × 4
10–15 yr (Senior): human = 56 + (cat_age − 10) × 4
15+ yr (Geriatric): human = 76 + (cat_age − 15) × 4
How it works
This calculator converts a cat's chronological age to a human-equivalent age using the life-stage framework recommended by the American Association of Feline Practitioners (AAFP) and the International Society of Feline Medicine (ISFM). The first year of a cat's life is equivalent to roughly 15 human years due to rapid physical and social development, the second year adds about 9 more, and subsequent years each add approximately 4 human years.
The calculator also assigns the AAFP/ISFM life stage label (Kitten, Junior, Prime, Mature, Senior, or Geriatric) so owners and vets can align preventive care to the appropriate life phase. Values are rounded to the nearest whole number.
Worked example
Worked example
- Cat age = 4 years, which falls in the Prime stage (2–6 years).
- Base at 2 years = 24 human years.
- Additional years: (4 − 2) × 4 = 8 human years.
- Total: 24 + 8 = 32 human years.
32 human years — life stage: Prime
Key terms
- AAFP/ISFM life-stage guide
- A framework from the American Association of Feline Practitioners and International Society of Feline Medicine that divides a cat's life into six stages to guide veterinary care.
- Prime stage
- The AAFP/ISFM life stage covering cats aged 3–6 years, during which cats are typically at peak physical condition.
- Senior cat
- A cat aged 11–14 years per AAFP/ISFM guidelines, equivalent to roughly 60–72 human years.
- Geriatric
- The final AAFP/ISFM life stage, applied to cats 15 years and older, comparable to a human in their late 70s or beyond.
- Chronological age
- The actual number of calendar years an animal has lived, as opposed to a biological or human-equivalent age.
Frequently asked questions
- How quickly do cats age?
- Cats mature very rapidly in their first year (equivalent to ~15 human years), then add around 9 more in year 2. After that ageing slows to roughly 4 human years per calendar year.
- What is a geriatric cat?
- Cats aged 15 years and older are considered geriatric by the AAFP/ISFM guidelines. They require more frequent veterinary check-ups.