Enter your cat age in years to see roughly how old they would be in human terms. Just like dogs, cats do not age at a simple steady rate, and the popular multiply-by-seven rule is inaccurate. Cats grow up fast: by the end of their first year a kitten is already comparable to a fifteen year old human, and by the end of the second year to about a twenty-four year old. After that, each additional cat year adds roughly four human years. This calculator applies that widely used feline aging model to give you a realistic estimate of your cat life stage, from playful kitten to dignified senior. It is a fun way to appreciate how quickly your companion matures. Everything runs locally in your browser with nothing stored anywhere.