Cats and dogs age somewhat differently, therefore calculating a cat’s age differs from dogs. The first year of life, a cat ages quickly, but slows down after that. Senior cats’ ages are similar to humans, but a bit faster.
A 6 month old cat is equivalent to a human 15 years old. A year old cat adds another 9 years to his age, making him the equivalent of a human 24 years old.
By the time your cat is 2 years old, he will begin to age 4 years for each year of his life.
According to experts there is no reliable methiod for calculating a cat’s age exactly. But this formula is workable and will give you your cat’s approximate age.