Cat Age Calculator
How old is your cat in human years? Convert using the veterinary chart — cats age fast early, then level off.
Example: with Your cat’s age 5 yrs → Human-age equivalent: 36 human years.
Computed by the calculator below using its default values. Change any input to see your own numbers.
Cat health and wellness resources
Learn moreFast start, slow finish
Cats mature quickly: the first year is roughly 15 human years and the second adds about 9 more, so a 2-year-old cat is around 24 in human terms. After that, each cat year is about 4 human years. It’s why kittens seem to grow up overnight.
How it’s calculated & sources
Year 1 ≈ 15 human years; year 2 adds ~9 (to ~24); each year after adds ~4. Life stage follows the AAHA/AAFP feline life-stage guidelines.
Benchmark: the AAHA/AAFP feline age conversion chart used by veterinarians.
Results update as you type and are general estimates, not personalized financial, tax, medical or legal advice. Verify with a professional.
Frequently asked questions
Do indoor and outdoor cats age differently?
Biologically the conversion is similar, but indoor cats typically live longer (often 13–17 years) thanks to fewer hazards.
When is a cat a senior?
Around 11 years. Many vets recommend more frequent checkups and senior bloodwork from that age on.