Cat Age Calculator
Enter your cat's age in years and months to see the human-equivalent age, life stage, and expected lifespan.
Calculator
Aging Timeline
How the cat age formula works
This calculator uses the AAFP/AAHA Feline Life Stage Guidelines: the first year counts as 15 human years, the second year adds 9 more (total 24), and every year afterward adds 4 human years. The formula is widely used by veterinary clinics because it captures how rapidly kittens mature in their first two years before settling into a slower aging curve.
Why know your cat's human age?
Knowing your cat's life stage helps you choose the right diet, schedule appropriate vet visits, and notice age-related changes early. Senior cats need different nutrition than kittens, and geriatric cats benefit from twice-yearly check-ups to catch kidney, thyroid, and dental issues before they become serious.
Reference Table
Quick lookup for cat age in human years using AAFP/AAHA Feline Life Stage Guidelines.
| Pet age (years) | Human age | Life stage |
|---|---|---|
| 1 | 15 | Junior |
| 2 | 24 | Adult |
| 3 | 28 | Adult |
| 4 | 32 | Adult |
| 5 | 36 | Adult |
| 6 | 40 | Adult |
| 7 | 44 | Mature |
| 8 | 48 | Mature |
| 9 | 52 | Mature |
| 10 | 56 | Mature |
| 11 | 60 | Senior |
| 12 | 64 | Senior |
| 13 | 68 | Senior |
| 14 | 72 | Senior |
| 15 | 76 | Geriatric |
| 16 | 80 | Geriatric |
| 17 | 84 | Geriatric |
| 18 | 88 | Geriatric |
| 19 | 92 | Geriatric |
| 20 | 96 | Geriatric |
| 21 | 100 | Geriatric |
| 22 | 104 | Geriatric |
| 23 | 108 | Geriatric |
| 24 | 112 | Geriatric |
| 25 | 116 | Geriatric |
Values use AAFP single-formula standard. Indoor cats typically live 4 years longer than outdoor cats but human-age conversion remains the same.
Sources & Citations
All formulas and life stage data are sourced from peer-reviewed veterinary publications and professional veterinary associations.
- AAFP/AAHA Feline Life Stage Guidelines
- Cornell Feline Health Center
- International Society of Feline Medicine (ISFM)
This calculator is for educational and informational purposes only. Always consult a licensed veterinarian for medical advice specific to your pet.
FAQ
How is cat age converted to human years?
The AAFP/AAHA Feline Life Stage Guidelines treat the first year as roughly 15 human years and the second year as 9 more (total 24). After year two, each cat year adds about 4 human years. So a 5-year-old cat is around 36 in human years.
What are the cat life stages?
Cat life stages are kitten (under 1 year), junior (1–2), adult (3–6), mature (7–10), senior (11–14), and geriatric (15+). These boundaries follow the AAFP guidelines used by most feline-only veterinary clinics worldwide.
How long do cats live?
Indoor cats typically live 13–17 years, while outdoor cats average 7–10 years due to higher exposure to traffic, predators, and disease. Sprint 1 of this calculator uses 15 years as the indoor default and 10 years for outdoor.