Dog age calculator
Enter your dog age, see it in human years.
How old is my dog in human years?
By the American Veterinary Medical Association chart for a medium dog (21–50 lb): 15 at age 1, 24 at 2, 28 at 3, then about 4 to 5 years per year — 60 at 10 and 87 at 16.
Is one dog year really seven human years?
No. The AVMA says dogs do not age at a rate of 7 human years per dog year — they age fastest in the first two years.
What is the DNA formula?
A 2020 study of DNA changes in 104 dogs (Wang et al., Cell Systems) proposed human age = 16 × ln(dog age) + 31. It gives 31 at age 1 and about 71 at 12. The dogs studied were mostly Labrador retrievers, so it fits them best.
Why do the two methods differ?
They measure different things: the chart compares life stages, the formula compares changes in DNA. Both are estimates.
Do big dogs age faster?
Size and breed matter: the AVMA notes that weight and breed influence aging, and large and giant dogs become seniors earlier than small ones.
How do I enter a puppy younger than one year?
The AVMA chart starts at 1 year, so the calculator shows only the DNA-based estimate below that age, from about 0.1 year (a little over a month). A 6-month-old puppy (0.5 year) comes to about 20 human years by the formula.
What does the AVMA chart do between whole years?
It interpolates in a straight line between the two nearest years. A 7½-year-old dog falls halfway between 47 at 7 and 51 at 8, which is 49.0 human years. The table in the result lists every whole year for both methods.
Two methods, two ideas of age
The AVMA chart is a table that matches life stages: a one-year-old dog is roughly a teenager and a two-year-old a young adult, then the chart adds about four to five human years for each dog year for a medium-sized dog (21 to 50 pounds). The DNA-based formula, published by Wang and colleagues in Cell Systems in 2020, compares the pattern of chemical marks on DNA (methylation) that change with age in dogs and in people, and fits the curve human age = 16 × ln(dog age) + 31. The first is a rule of thumb for life stage; the second is a measurement-based fit.
Worked example: a medium dog at 1, 5, 10 and 12 years
By the AVMA chart a 1-year-old dog is 15 human years, a 2-year-old 24, a 5-year-old 36, a 10-year-old 60 and a 12-year-old 69. The DNA formula gives 31, 42, 57, 68 and 71 for 1, 2, 5, 10 and 12 years. The two agree in the senior years (69 against 71 at 12) and disagree most in the first two years, because the formula is a smooth logarithm that starts higher, while the chart is a table of life stages. Neither is a diagnosis: they are ways to compare a dog's life stage with a person's.
Common mistakes
The first is the old multiply-by-seven rule, which the AVMA says is not accurate. The second is applying a medium-dog chart to a giant breed, which reaches old age sooner, or to a small dog, which often lives longer; the AVMA chart in this calculator is for a dog of 21 to 50 pounds. The third is using the formula far outside the range of the study, for example for a 20-year-old dog. Finally, the age in human years does not tell you how much exercise, food or veterinary care a dog needs; ask your veterinarian about your dog's life stage.
Sources: American Veterinary Medical Association, “Pets age faster than people” (dog age chart for medium dogs); Wang, T., Ma, J., Hogan, A. N. et al., “Quantitative translation of dog-to-human aging by conserved remodeling of the DNA methylome,” Cell Systems 11 (2020). Related: cat age calculator, age calculator, pet calorie calculator and life in weeks calculator.