Dog age calculator
How old is your dog in human years? Enter their age and size.
How we calculate it
The first year of a dog's life is roughly equal to 15 human years and the second to about 9 more. After that, each year adds about 4 human years for small dogs, 5 for medium, 6 for large and 7 for giant breeds. These are rounded averages: genetics, health and breed all play a part.
We also show the estimate from a 2019 study that compared DNA changes in dogs and people (human age ≈ 16 × ln(dog age) + 31). It isn't size-specific, so treat the two numbers as a range.
Questions people ask
Is one dog year really seven human years?
No. Dogs mature much faster in their first two years: a 1-year-old dog is roughly like a 15-year-old person, and a 2-year-old is roughly 24. After that, ageing slows down, and bigger dogs age faster than small ones.
Why do large dogs age faster?
Large and giant breeds tend to have shorter lifespans and reach their senior years earlier than small breeds, so each year after age two counts for more human years.
When is a dog considered a senior?
It depends on size. Giant breeds can be seniors from about 6, large dogs from about 7, medium dogs from about 8 and small dogs from about 10.
What is the DNA-based dog age formula?
A 2019 study of DNA changes in Labrador retrievers suggested human age ≈ 16 × ln(dog age) + 31. It is based on one breed, so we show it as a second estimate alongside the size-based chart.