Cat Years Calculator
Convert cat years to human years with the vet age formula and AAFP/ICatCare life stage. Free online cat age calculator, indoor vs outdoor lifespan.
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How to use Cat Years Calculator
- 1Enter your cat's age in years and months
- 2Pick the lifestyle — indoor-only or indoor/outdoor access
- 3Press Calculate to see the age in human years, the AAFP/ICatCare life stage and the average lifespan, then open the full chart
Frequently asked questions
Is one cat year really seven human years?▾
No. The 1:7 rule is a myth. Cats mature very fast: a one-year-old cat is about 15 in human years and a two-year-old about 24. After that each year adds about 4 human years.
How old is my cat in human years?▾
Using the vet formula, a 5-year-old cat is about 36, a 10-year-old about 56, and a 15-year-old about 76 in human years.
What are the cat life stages?▾
The AAFP/ICatCare classification has six stages: Kitten (0-6 months), Junior (6 months-2 years), Prime (3-6 years), Mature (7-10 years), Senior (11-14 years) and Geriatric (15+ years).
Do indoor cats live longer than outdoor cats?▾
Yes, significantly. Indoor-only cats typically live 12-18 years, protected from traffic, predators and disease, while cats with regular outdoor access face much higher risks and often live a shorter, more variable lifespan.
When is a cat considered a senior?▾
Vets classify cats as senior from about 11 years old, and geriatric from 15 years old, regardless of breed — unlike dogs, size has little effect on a cat's aging pace.
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