How old is my pet in human years?
Pick dog or cat, the size and the age. Size matters: a 10-year-old Chihuahua and a 10-year-old Great Dane are not the same age at all.
The newer DNA-based formula (16 × ln(age) + 31) puts your dog at about 53. It runs higher early in life and lower later.
How we calculate it
We use the size-adjusted method many vets use: the first year counts as about 15 human years, the second as about 9 more, and every year after adds 4 (small dogs and cats) up to 7 (giant breeds). For dogs we also show the newer DNA-methylation formula from researchers at UC San Diego for comparison.
FAQ
Is one dog year really seven human years?
No. Dogs mature very fast in the first two years (roughly 15 human years in year one and 9 more in year two), then age more slowly. Larger dogs age faster than small dogs after that.
How old is a cat in human years?
A one-year-old cat is roughly 15 in human years, a two-year-old about 24, and each year after that adds around 4 human years.
Why do big dogs age faster?
Researchers are still working out why, but large and giant breeds reach old age sooner and usually have shorter lifespans than small breeds.