How To Calculate Your Dog’s Real Age
We’ve all heard the rule that one year in a dog’s life is equal to seven years in a human’s. It should come as no surprise that this rule isn’t a good one to go by since that would mean that some dogs tend to live to the age of 70 while others live to be more than 120 years old! This discrepancy is due in part to the size and breed of dogs and also to the differences in the way they mature.
Dogs don’t develop at the same rate during each year of their lives, with the greatest difference between them and humans occurring during their first year. Learning how to calculate your dog's real age can help you give it the most appropriate care at all stages of its life.
Most humans are barely capable of walking and speaking at the age of one year, but dogs mature much more quickly. Puppies don’t stay little for very long, reaching the equivalent of fifteen years in human age during their first year of life. That means that your one-year-old dog is actually comparable to a human teenager!
The faster aging continues through their second year, with a two-year-old dog being equal to twenty-four years in human years. After that, aging continues to slow each year but it isn’t until the sixth year that there begin to be differences according to the size and breed of the dog.
 |  |  | |
Size Of Dog | SMALL 20 Pounds or Less | MEDIUM 21 to 50 Pounds | LARGE Over 50 Pounds |
| Age Of Dog | Age In Human Years | ||
| 1 | 15 | 15 | 15 |
| 2 | 24 | 24 | 24 |
| 3 | 28 | 28 | 28 |
| 4 | 32 | 32 | 32 |
| 5 | 36 | 36 | 36 |
| 6 | 40 | 42 | 45 |
| 7 | 44 | 47 | 50 |
| 8 | 48 | 51 | 55 |
| 9 | 52 | 56 | 61 |
| 10 | 56 | 60 | 66 |
| 11 | 60 | 65 | 72 |
| 12 | 64 | 69 | 77 |
| 13 | 68 | 74 | 82 |
| 14 | 72 | 78 | 88 |
| 15 | 76 | 83 | 93 |
| 16 | 80 | 87 | 120 |
When it comes to longevity, this is one time that bigger isn’t better. Small breeds tend to live longer than larger breeds, explaining why some efforts have been made to introduce miniature breeds of favorites. This is also one way that undesirable traits like hip dysplasia or cancer may be “bred out” of some breed lines.
Mixed Breed Dogs
The debate over which lives longer, mixed breed dogs or purebreds, is one that has been consistent through the ages. The argument in favor of mixed breeds being healthier is based on the assumption that genetic disorders that are found in large number within members of certain breeds occur less frequently in mixed breed dogs.
Research has proven out that , in fact, a greater number of occurrences of some of these disorders did occur in purebred dogs in comparison to those who were of mixed breeds, there were no differences found in the incidence of numerous disorders between the two groups. Only one disorder, ruptured cranial cruciate ligament, was found more frequently in mixed breeds.
So, how do you calculate the true age of a mixed breed dog? The best method is to estimate the age in human years according to the size of the dog. Most will be somewhere between that of the mother and father, often putting it into the same category as either or both parents.
Adopted Dogs
If you have adopted a dog or taken in a stray, you may not have its age in years to use as a reference. A trip to the vet will give you the information you need to at least get in the ballpark of how old your dog is so you can do the calculation into human years.
Vets typically estimate the age of puppies due to the presence or absence of teeth. Dogs that are older may also have tell-tale signs in their teeth that will provide an approximate age. The vet will also be able to tell you if there are any dental problems that need to be addressed, especially if your dog is older.
Why Age Matters
Every dog has changing needs that will need to be met at every phase of their lives. The food that provides the right nutrition for a puppy isn’t the same as that needed for a senior dog that is less active. Older dogs also need different types of toys to keep them entertained and they are more vulnerable to some types of health conditions.
Knowing your dog’s age and phase in life will let you know what types of accommodations to make for him.
It might not seem like these differences matter. But when you consider dogs at the opposite ends of the scale, a Chihuahua is considered a senior when it reaches twelve years of age while a Great Dane is considered a senior at just six years old!
Calculating your dog’s age isn’t something that you do just for fun. It is a reference that lets you know how to provide the best care and keep him happy and healthy throughout his lifetime.