Calculating a Dog's Age
It's common knowledge that dogs age faster than people. But the conventional wisdom that one dog year equals seven human years is an oversimplified view of how old your dog is in human years. Although a dog's age averages out this way, there is quite a bit of variation. For example, dogs mature more quickly than children in the first couple of years. So the first year of a dog's life is equal to about 15 human years, rather than seven.
Size and breed also influence the rate at which a dog ages. Although smaller dogs tend to live longer than larger dogs, they may mature more quickly in the first few years of life. A large dog may mature more slowly at first but already be considered elderly at age five. Small and toy breeds don't become "seniors" until around age 10. Medium-sized breeds are somewhere in the middle in terms of maturation and lifespan.
In the chart below, use these general ranges for dog size:
Translating Dog Years into Human Years
How to Determine a Dog's Age
If you've adopted a puppy or dog but don't know the dog's history, you may wonder how old your dog is. Even if you don't know the birth date, it is still possible to estimate your dog's age.
Teeth can give a rough indication of a dog's age. The degree of growth helps determine how old a puppy is, and the degree of wear and tartar helps estimate the age of an adult dog. Of course, there are individual differences between dogs. And a dog's previous dental care will have an impact on the health of teeth.
Here are some general guidelines:
Your vet can also estimate your dog's age based on a complete physical exam or tests looking at bones, joints, muscles, and internal organs. In older dogs, signs of aging may show up in a variety of ways, including: