Cat Age in Human Years Calculator
Convert your cat's age to human years using veterinary research-based formulas.
What is Cat Age in Human Years Calculator?
The cat age calculator applies the veterinary consensus: cats age fast in early years, then about 4 human years per cat year after age 2.
Formula
Year 1 = 15. Year 2 = +9. Each year after = +4.
Worked example
5-year-old cat: 15 + 9 + (3 × 4) = 36 human years (prime adult).
How to use this calculator
- Enter cat's age in years.
- Equivalent human age and life stage appear.
Frequently asked questions
Indoor vs outdoor lifespan?
Indoor cats: 13–17 years average. Outdoor cats: 5–7 years (predators, traffic, disease). Indoor-only is the single best longevity decision for cat owners.
When is a cat "senior"?
Senior: 11–14 years. Super senior: 15+. Senior care includes more frequent vet visits, kidney function monitoring, and dietary adjustments.
Do all cats age at the same rate?
Generally yes, less size variation than dogs. Some breeds (Siamese) tend toward longer lives; some (Maine Coon, Persian) slightly shorter due to genetic predispositions.
Oldest cat?
Verified: Creme Puff lived 38 years (2005). Average is 13–17. Cats over 20 are uncommon but not rare with good care.