Dog Age Calculator — Dog Years to Human Years
Convert your dog's age to human years using the DNA methylation formula — more accurate than the '×7' rule. Includes breed size adjustments and life stage information.
About the Dog Age Calculator — Dog Years to Human Years
Your 3-year-old dog is not equivalent to a 21-year-old human. Scientists at UC San Diego developed a more accurate dog-to-human age conversion based on DNA methylation changes — the same biological marker of aging used in humans. Our calculator uses this formula, adjusted for your dog's breed size.
Larger dogs age faster than smaller breeds — a 10-year-old Great Dane is much older in biological terms than a 10-year-old Chihuahua. Select your dog's size category for the most accurate human-age equivalent.
Why the '×7 rule' is wrong
The popular '1 dog year = 7 human years' rule ignores the non-linear nature of canine aging. Dogs mature extremely rapidly in their first 2 years: a 1-year-old dog is sexually mature and has completed most physical development — equivalent to roughly a 15-year-old human. Growth then slows. A 10-year-old medium dog is closer to 68 in human years, not 70. The UCSD DNA methylation formula: Human Age = 16 × ln(dog age) + 31.
Small vs. large breed aging differences
Paradoxically, large breeds age faster despite maturing more slowly as puppies. A 10-year-old Chihuahua has a much longer statistical life expectancy than a 10-year-old Mastiff. Large breeds are more susceptible to age-related diseases (especially cancer and joint disease) and generally live 8–10 years vs. 14–16 years for small breeds. The formula adjusts the human equivalent age accordingly.