It is a common belief that 1 human year is equal to 7 dog years. That is not very accurate, since dogs reach adulthood within the first couple of years. This formula is a bit more accurate.

Age of Dog        Human Years

1 year                  15 years
2 years                24 years
3 years                28 years
4 years                32 years
5 years                36 years
6 years                40 years
7 years                44 years
8 years                48 years
9 years                52 years
10 years                56 years
11 years                60 years
12 years                64 years
13 years                68 years
14 years                72 years
15 years                76 years
16 years                80 years
17 years                84 years
18 years                88 years
19 years                92 years
20 years               96 years