Dog Age Calculator — Convert Dog Years to Human Years

Converting dog years to human years is more complex than multiplying by seven. Dogs age rapidly in their first two years and then slow down — but the rate depends heavily on breed size. This calculator provides two scientifically grounded methods so you can see both perspectives.

AKC / AVMA Size-Adjusted Method

The American Kennel Club and American Veterinary Medical Association use a size-adjusted model. All dogs reach roughly 15 human years after their first year of life and 24 human years after their second year. After that, smaller dogs age more slowly per calendar year than larger dogs:

• Small breeds (under 20 lb): approximately 4 human years per dog year after age 2
• Medium breeds (20–50 lb): approximately 5 human years per dog year after age 2
• Large breeds (50–100 lb): approximately 6 human years per dog year after age 2
• Giant breeds (over 100 lb): approximately 7 human years per dog year after age 2

UCSD Epigenetic Formula

Researchers at the University of California San Diego developed a formula based on DNA methylation analysis — measuring chemical changes to DNA that correlate with aging. Their formula is:

This formula does not depend on breed size and provides a useful scientific comparison. Notice that the epigenetic method tends to give higher human-age equivalents for younger dogs and lower equivalents for very old dogs compared to the AKC method.