The belief that your pooch age seven years for each human year stems from the fact that the average lifespan of a dog is about one seventh that of a person’s. However, determining the exact age of a pooch (relative to a human scale) is actually much more complex. Here are some contributing factors:

Breed: Large breeds such as Mastiffs and Newfoundlands typically live nine to 11 years, while small or toy breeds such as Chihuahuas and Toy Poodles can live 18 to 21 years.  

Different ageing rate: Ageing is much quicker during the first two years of a dog’s life. It turns out, the first year of a dog’s life, regardless of breed, is about the same as 14 to 15 human years. 

Size Matters
Afterwards, depending on the dog’s size, the number of doggy years corresponds to a different number of human years, with this scale varying from breed to breed. This is why smaller breeds tend to live longer than their larger counterparts.

Other things like the weight and health condition of the dog can also affect its lifespan.

And Cats?
Cats normally live till about 14 to 18 (human) years, but some can survive well into their early twenties. Their lifespan also depends on their breed. For instance, Siamese cats tend to live longer.

The general rule of thumb is that felines’ early years equal to seven human years, while later years translate to about five.

*This article was updated on 25 Jul 2020. It first appeared in on 10 Nov 2016.