Determining Dog Age in "Dog Years"
The rule to calculating a dog's age used to be 7 dog years for every 1 human year; however, this has been adjusted to a more realistic calculation as dog's mature quickly during the first 2 years of life and because different size dogs age at different rates when comparing to human lifespan. Small to medium sized dog's age at a general rate of 5 years to every 1 year after the first 2 years of life. Large dogs age at 6 to 1 and giant dogs at 7 to 1.
Determining a dog's longevity is an approximate process that can help you determine how old your dog is in human terms; however environment, health, genetics, size, breed mixes and individual variations all play significant roles in determining the specific age and lifespan of a dog and must be considered.