What is the average life expectancy for dog?

The life expectancy of a dog can be anywhere from 7-14 years.It depends on the dog. Purebreds are more prone to disease while muts tend to be healthier, and larger dogs are prone to joint and heart problems. My dad had a smaller size mutt that lived to be 21! which is unusual by any means but is a good example of the type of dog that will live longer. I on the other hand have a purebred bernese mountain dog and they aren't expected to live past 10 :-(.