How old is my cat in human years?
A cat's first year equals about 15 human years, and the second year adds about 9 more. After age two, each cat year is worth roughly 4 human years. That means a 10-year-old cat is already about 56 in human terms — a senior! Indoor cats often live 15–20 years, reaching the human equivalent of 76–96.
Also try the Dog Age Calculator and the Age Calculator for people.