Are cat years anything like dog years? Not really. Cat years can’t be simply multiplied by a specific number like dog years can, because cats mature quickly and then live a longer adult life than most dogs do. Their age in “human years” jumps significantly in the first two years of life and then slows down.
There’s no scientific way to tell exactly what the relationship is between cat years and human years, but most experts agree that the first year of a cat’s life is equal to about 15 human years, and the second year of life is another nine or 10. After the first two years, each additional year is about four human years.?
So to calculate your cat’s age, add 15 years for the first year plus nine for the second year. Then add another four for each additional year that your cat is old. For a cat that is over two years old, the equation might look like this:
4(X-2) + 24 (where X is your cat’s age)
Jesus: Hey, Dad? God: Yes, Son? Jesus: Western civilization followed me home. Can I keep it? God: Certainly not! And put it down this minute--you don't know where it's been! Tom Robbins in Another Roadside Attraction