How to Calculate Your Pet's Age in Human Years

By Linda Cole

Advances in medicine over the years have increased our life spans through better diagnosis and treatments. Veterinarian medicine has also given our pets a boost in their life span. When trying to figure out what your pet's age is, the old school of thought has been 1 year in dog years equals 7 years in human years. It seems that scale is now obsolete. But what about cats? If the old formula has changed, how do you calculate your pet's age in human years?

Our age gives someone an idea as to what our level of experience is according to how old we are. Age can indicate if someone is mature enough to handle certain responsibilities or young enough to still require supervision. For us, age tells us if someone is in their golden years, middle aged or still wet behind the ears. Our pets also mature at a certain age, but because they have a shorter life span, they age faster than we do.

Calculating your pet's age gives you an idea of what their chronological age is. Figuring out our pet's age in human years helps to see them at their actual age as they grow older. A 7 year old dog or cat is approaching middle age and is about 44 years old by our standards. By her tenth birthday, she's 56 according to human age and not far from her golden years. Using the old formula of 1 dog year equals 7 human years is simple and easy to remember, but it doesn't give an accurate calculation when comparing a pet's age to humans. For example, a cat or dog who has reached their first birthday is able to reproduce; a 7 year old child has a ways to go before they reach that milestone.

In the 1950s, a French veterinarian named Monsieur LeBeau devised a new way to calculate our pet's chronological age by using their average life expectancy (the number of years a species can expect to live) compared to the maximum number of years they can live (the age where no person or animal can live past). Modern medicine has increased the average life expectancy for both humans and animals, and that's why the LeBeau formula is more accurate in determining your pet's age. Different breeds of dogs have different life expectancy and smaller dogs and cats have a longer average life expectancy than larger dog breeds.

Using this new calculation, a one year old pet has matured at the same level as a 15 year old human. At age two, your pet's age equals a 24 year old person. We are considered to have reached maturity at age 24. So pets are fully matured at age two. Every year after two, add 4 human years to 24. A three year old pet is 28 and a 12 year old pet is 64 years old in human years. This gives you a more accurate chronological accounting of your pet's age according to his aging process.

One interesting thing about LeBeau's formula is that after the age of 14, cats and dogs begin to differ in age as they grow older. A 15 year old cat is considered to be 74 where the dog's age goes to 74.5. At 18 years of age, the cat is 80 and the dog is 82. And the 20 year old cat is 84 and the dog is 87.

The maximum life span for humans is considered to be around the age of 110. Dogs are thought to be able to live no longer than 29 years and cats can reach a maximum age in their mid 30s. So taking the differences in maximum life span for humans compared to cats or dogs, the dog's age after age 14 is calculated at two and a half human years compared to two years for cats. So that's why a 20 year old cat is chronologically younger than a 20 year old dog. The cat has a longer maximum life span.

Like us, our pets have different factors that help enable them to live a long life. Nutrition, exercise, genetics, and social and mental stimulus all play a role in your pet's health as well as life expectancy. Your pet's age in human years gives you an idea of where they are chronologically and helps you provide for them as they age. You can be a responsible pet owner by making sure your dog or cat eats high quality pet food and gets proper exercise. Lots of mental and physical stimulus helps keep their mind active, and regular vet care throughout their life can help your pet reach their golden years. This will give you plenty of time to enjoy their love and companionship.

Read more articles by Linda Cole