Is a "Dog Year" Really 7 "Human Years?"
Not really. The idea that a “dog year” is equal to 7 “human years” is based on the idea that dogs live an average of ten years, while humans live an average of 70 years. However, this would mean that a year old dog would be the same maturity as a seven-year-old. But a year old dog is often already mature!
So how can we figure out the “equivalent age” of a dog to a human?
First, we’ll take a few snapshots of both a human’s life and a dog’s life. We already have one - average age. Another one is maturity. Let’s say a dog reaches maturity at a year old (Wikipedia says six months to twelve months, or even up to two years for larger dogs!) and people reach maturity at 18.
What other snapshots can we take?
Senior age. For the purpose of this post, we’ll assume a dog is senior at 8, while a human is senior at 55 (at least that’s what restaurant menus say!)
There’s probably more, but these three a probably a good start. To recap, they are:
| snapshot | dog age | human age |
|---|---|---|
| maturity | 1 year | 18 years |
| senior | 8 years | 55 years |
| death | 10 years | 70 years |
Using these snapshots, I’d guess that a 3-year old dog is about 28 human years.
How accurate is this?
WebMD has an interesting chart that includes dog size in the age guess. A 3-year old dog is 28 in human years across all three sizes. The ages don’t change amongst the sizes until 6 years.
Calculator
I’ve created this calculator for you to mess around with. You can edit the snapshot comparisons and see how it affects a dog’s age in human years:
| snapshot | dog age | human age |
|---|---|---|
| maturity | ||
| senior | ||
| death | ||
| age |