Tailyears
CalculatorsBreed lifespansHow long do dogs liveSenior careInsurance

Dog years to human years

A one-year-old dog is a teenager, a two-year-old is 24, and after that the pace depends on size. Enter your dog's age below.

Sets the size class and life stages. Leave empty and pick a size below for mixed breeds.
Toy under 12 lb · Small 12–28 · Medium 28–55 · Large 55–100 · Giant over 100 lb
Your dog's age in human years
36human years
Size-adjusted chart (AVMA style). The epigenetic clock, calibrated on Labradors, says 57: it ages dogs faster early and slower later.
  • Life stage nowmature adult
  • Senior from about8 years
  • Typical lifespan for this size or breed10–14 years
  • Roughly the human equivalent ofa 36-year-old

Why "seven dog years per human year" is wrong

The 7:1 rule came from dividing a human lifespan of about 70 by a dog lifespan of about 10. It ignores that dogs reach sexual maturity in their first year and that big dogs age faster than small ones. A Great Dane is elderly at 7 while a Chihuahua at 7 is middle-aged.

Size-adjusted charts fix the first problem by front-loading the early years. The 2020 epigenetic clock from the University of California San Diego fixed it differently, by measuring how DNA methylation patterns in dogs line up with those of humans of a known age. Both agree on the big picture: dogs are "adults" by two and "seniors" in the last quarter of their expected lifespan.

For the full chart and the maths, see the dog age calculator. To see when your breed becomes a senior, use the senior dog age calculator.

Frequently asked questions

How many dog years are in a human year?

It changes with age and size. The first dog year is worth about 15 human years, the second about 9, and each year after that about 4 to 7 depending on how big the dog is.

How old is a 10-year-old dog in human years?

About 56 for a small dog, 64 for a medium dog, 72 for a large dog and 80 for a giant breed on the size-adjusted chart. The epigenetic clock gives 68 regardless of size.

How old is a 2-year-old dog in human years?

Around 24 on the size chart. Dogs of all sizes are fully adult by two.

Sources

  1. Wang T, Ma J, Hogan AN, et al. Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome. Cell Systems. 2020;11(2):176-185. doi.org/10.1016/j.cels.2020.06.006
  2. Creevy KE, Grady J, Little SE, et al. 2019 AAHA Canine Life Stage Guidelines. Journal of the American Animal Hospital Association. 2019;55(6):267-290. www.aaha.org/resources/life-stage-canine-2019/
  3. McMillan KM, Bielby J, Williams CL, Upjohn MM, Casey RA, Christley RM. Longevity of companion dog breeds: those at risk from early death. Scientific Reports. 2024;14:531. doi.org/10.1038/s41598-023-50458-w