Cat Age Calculator
How old is your cat really in human years? Work it out with the official formula and get advice that fits each life stage.
Converting cat years to human years
‘How old is my cat in human years?’ is perhaps the question every cat owner asks at some point. The well-known answer — cat years times seven — sadly isn’t right. Cats develop incredibly fast in their first years and much more gradually after that. This free calculator therefore uses the rule of thumb that vets apply: enter your cat’s date of birth or age and you’ll instantly see the human age, the matching life stage and fitting care advice.
The formula: 15, +9, then +4 per year
The conversion works like this: the first cat year represents roughly 15 human years — from helpless kitten to almost-grown cat in twelve months. The second year adds another 9, so a 2-year-old cat is comparable to a 24-year-old human. From then on it slows down: every extra cat year equals about 4 human years. A 5-year-old cat is therefore around 36 in human years, a 10-year-old about 56 and a 15-year-old already 76. The calculator counts in-between months proportionally, so the age of, say, a 7-month-old kitten is right too.
Besides the number you see your cat’s life stage — kitten, junior, adult, senior or geriatric — with concrete advice on nutrition, vet visits and care for each stage. If you’ve created a cat passport, the date of birth is ready for you and the result is saved automatically. For the very youngest cats the kitten planner is a logical next step, with growth curve and vaccination schedule.
How old does a cat get on average?
A healthy house cat lives 12 to 18 years on average, and outliers into their early twenties are common. Indoor cats usually live longer than outdoor cats because they face fewer risks from traffic, fights and disease. Good nutrition, a healthy weight and annual check-ups make a big difference — take a look at the feeding planner too.
Is the rule ‘1 cat year = 7 human years’ correct?
No. By that rule a 1-year-old cat would be a 7-year-old child, while in reality it is already almost an adult. The 15/+9/+4 formula follows cats’ real development much better: quickly adult in the first two years, then a steady pace.
From what age is a cat a senior?
Vets consider a cat a senior from about 7 years and geriatric from 12 years. From the senior stage a check-up twice a year is wise, including blood and urine tests, because kidney and thyroid problems often start insidiously.
How old is my cat if I don’t know the date of birth?
No problem: in the calculator you can simply enter an estimated age in years and months. A vet can also estimate a cat’s age reasonably well from its teeth, eyes and coat.