Pet age calculator
Dog or cat age in human years.
Put this calculator on your site
Get it as a ready-made Gravity Forms template. Import it, match your colors, publish.
- Import-ready form file
- Step-by-step build guide
- Works with any theme
How it's calculated
Seven dog years to one human year is wrong: puppies and kittens mature fast, then age slows down. The rule vets use counts the first year as 15 human years and the second as 9 more, so a two-year-old is about 24. After that each year adds 4 for a cat, and for dogs about 4 for a small breed up to 7 for a giant one, because big dogs age faster and live shorter lives. A 2019 study of dog DNA (16 × ln(age) + 31) agrees for Labradors and puts a one-year-old at about 31; the simple rule is close enough for a birthday card.
Is one dog year really seven human years?
No. The seven-to-one idea came from dividing a 70-year human life by a 10-year dog life. Dogs reach adulthood by one, so the early years count for much more and the later years for less. Size matters too: a Great Dane is old at seven, a Chihuahua is middle-aged.
Why do big dogs age faster?
Nobody is sure. Large breeds grow much faster as puppies and seem to pay for it with earlier wear: giant breeds live 7–10 years against 14–16 for small ones. The size-based rate in this tool reflects that difference.
How old is a 10-year-old cat in human years?
About 56: 24 at two, plus eight years at four each. Indoor cats commonly reach 15–20, which is the human 76 to 96. Cats are considered senior from about 11 and geriatric from 15.
Results are estimates for informational purposes only and are not financial, medical or legal advice.