How “old” is your Dog?

Calculating Dog Years versus Human Years

Calculating out how old your dog is relative to human age isn’t as simple as people think. A number of factors come into play.

The first factor is a dog’s size and/or breed. For instance, a Bulldog’s life expectancy is estimated to be around 7 years, and Great Dane lives to be 8.5 years on average. Compare that to a Miniature Poodle whose average lifespan is close to 15 years. So the breed makes an enormous difference in the number of years a dog will live.

Because we are comparing dog years to human years, we also have to consider the average life expectancy of humans. For instance, if we assume a certain breed of dog lives 10 years on average, and put that into the calculator, the result should be the maximum lifespan of a human. But human life expectancy varies, based on things like infant mortality, country, access to health care, gender, etc. Average lifespan worldwide is around 66 years. In developed countries, it is 80 years, and that is what the calculator above assumes.

As you can see, a truly accurate calculator could get cumbersome. So the dog years calculator above simply takes a middle-ground approach that is accepted as adequate by many people. For the first two years, a dog year is equal to 10.5 human years. After that, each dog year equals 4 human years. This calculation is based on studies that indicate dogs, except maybe larger breeds, develop more quickly in the first two years of life.

A method of calculating your dogs’ age
Dogs < 9 k 10 – 23kg 24 – 41kg 42kg+ Age 1 15 15 15 9 2 24 24 24 17 3 28 28 28 26 4 32 32 32 33 5 36 36 36 42 6 40 42 45 50 7 44 47 50 56 8 48 51 55 64 9 52 56 61 71 10 56 60 66 78 11 60 65 72 86 12 64 69 77 93 13 68 74 82 101 14 72 78 88 15 76 83 93 16 80 87 99 17 84 92 Dog Dog Dog Dog Years Years Years Years