How to Calculate a Dog's Age in Dog Years

A popular misconception is that dogs age 7 years for each calendar year. In fact, canine aging is much more rapid during the first 2 years of a dog's life. After the first 2 years the ratio settles down to 5 to 1 for small and medium breeds. For large breeds the rate is 6 to 1, and for giant breeds the rate is 7 to 1. Thus, at 10 years of age a Great Dane would be 80 years old while a pug would only be 64.

How to Tell a Dog's Age

If you've taken in a dog whose age is unknown, there are some ways to determine his age. Here are some things vets check to get a general sense of how old a dog is:

The Teeth: Dogs usually have a set of permanent teeth by their seventh month, so if you've come across a dog with clean pearly whites, he is likely a year old or thereabouts. Yellowing on a dog's back teeth may put the dog between one and two years of age, while tartar build-up at a minimal level could mean you have a dog between 3 and 5. Missing teeth or severe wear usually means the dog is a senior and could use some special dental care.

Muscle Tone: Younger dogs are more likely to have some muscle definition from their higher activity level. Older dogs are usually either a tad bonier or a little fatter from decreased activity.

The Coat: A younger dog usually has a soft, fine coat, whereas an older dog tends to have thicker, coarser (and sometimes oilier) fur. A senior dog may display grays or patches of white, particularly around the snout.

The Eyes: Bright, clear eyes without tearing or discharge are common in younger dogs. Cloudy or opaque eyes may mean an older dog.

Use this chart to calculate your dog's age:

Old Age in Dogs

The age at which a dog can be considered elderly varies widely among models. In general, the larger the dog, the more quickly it declines. For instance, a Great Dane could be considered "senior" at age 5, while a smaller toy poodle would still be spry at twice that age. Remember, however, that just because a dog is chronologically old doesn't mean that an endless series of malfunctions is in store. In many cases an elderly dog can enjoy many healthy, active, pain-free years.

One of the best ways to prolong the life and improve the functions of an elderly dog is to carefully regulate its fuel intake. Older dogs exercise less and thus need fewer calories. And since age reduces their ability to digest and absorb nutrients, high-quality food specifically formulated for their needs is a necessity. Excessive amounts of protein, phosphorus, and sodium can aggravate kidney and heart problems, so most such foods contain smaller amounts of higher-quality protein, along with reduced quantities of other elements. Levels of vitamins, zinc, fatty acids, and fiber, however, are increased.