Tool · Dogs
How old is my dog in human years?
The “one dog year equals seven human years” rule is a myth. A 2020 study found dogs age very fast early on, then slow down.
Where the formula comes from
Researchers compared chemical changes to DNA that build up with age (called methylation) in more than 100 Labrador retrievers and in people. They matched the patterns into this formula: human age = 16 × ln(dog age) + 31, where ln is the natural logarithm.
It means a 1-year-old dog is roughly like a 31-year-old person in DNA terms, a 4-year-old like a 53-year-old, and after that ageing slows down.
How good is this formula?
Early evidenceIt comes from a single study of one breed. Large breeds tend to live shorter lives than small ones, so it may fit some dogs better than others. It works best for dogs aged 1 and over.
Sources: BBC Science Focus on the 2020 Cell Systems study. Not reviewed by a vet.