How old is my dog in human years? Would you like to know how old your dog is in man-years? You can enter either the date of birth or age and this app will calculate it for you.   The science behind a dog's age This app is using a new formula, which was published by a team of scientists from the University of California, San Diego. Their assumption is that all dogs, regardless of breed, follow a similar developmental trajectory, with puberty reached at 10 months and dying before 20 years. You