University of California San Diego School of Medicine researchers came up with a new formula to determine determine how “old” your dog is. They say that their study showed that “dogs age at a much faster rate than humans early in their lives, then slow down after reaching maturity.” So based on the study, a one-year-old dog would be comparable to a 30-year-old human and a dog that’s 4 would be comparable to 52-year-old human. After a dog turns 7, the aging process slows down, according to the study.