How Your Pet Ages

Have you ever wondered how long your dog has been alive in human years? It is hard to know because dog years and human years are quite different. Here are some tips on calculating dog years to human years so you can figure out just how old your furry friend is in relation to you.

The Origin of the 7-Year Rule

The most popular school of thought on how to calculate dog years is a formula that estimates the average lifespan of a dog at seven human years per one canine year. This figure is derived from an estimate that dogs age seven faster than humans. To determine how old your pup is in human years per this methodology, simply divide his current age by 7. For example, if your pup is 3, he should be 21 in human years.

The origin of that calculation remains shrouded in mystery, but there are a few different theories about its origins. One theory traces its roots back to English poet Robert Burns, who believed that dogs only live seven times faster than humans. That would make their life expectancy ten years old or the equivalent of around 70 human years. 

Another theory says it has to do with wolves. Wolves have been known to live up to 16 years, so someone once assumed that every year in a wolf's life was equal to six years in a human's life. That would make 16 wolf years equal 96 human ones — or about 14 dog years worth!

While both theories are interesting, it is hard to say with certainty how they started. What we do know is that while dogs may age faster than humans, they don't have a set lifespan, which means there is no exact formula you can use to convert their years into ours.

The 7-Year Rule is a Myth

One dog year does not equal seven human years. In fact, the 1-to-7 ratio is so off that it would mean a 10-year-old Labrador retriever would be the equivalent of a 70-year-old person! This disproves the long-believed theory of one dog year being equivalent to seven human years. 

The truth is, there is no consistent formula for converting dog years into human ones.

Some believe that a more accurate conversion factor is 4:1. To determine your pup's age in human years, you multiply your dog's age by 4. So if you have an 8-year-old German Shepherd, he would be 32 in human years. If you had a 3-year-old English Bulldog, he would be about 12. And if you had a 2-week-old Pug puppy, she would be about two months in human years.

There are also those that believe one dog year is equivalent to 6 human years. If your pooch is 10, he would be 60 in human years. That same 3-year-old English Bulldog would be about 18 in human years. And that 2-week old Pug puppy would be about three months in age. 

A More Accurate Way to Calculate Your Dog's Age in Human Years

If you are trying to determine your dog's age in human years more accurately, the team of researchers at the UC San Diego School of Medicine has created a formula that can be of use to you.

The results of this study revealed that dog DNA evolved over time. In particular, the researchers analyzed patterns of methyl groups in humans and Labrador Retrievers. They found that the most reliable way to calculate a dog's age was by multiplying the natural logarithm of the dog's age by 16 and adding 31 or (human_age=16ln(dog_age)+31). If you find this formula too complex, you are not alone. Thankfully, online calculators like this can do the math for you, so you don't have to. 

If you have a small, medium, or large dog under 100 pounds, you can also use this methodology by American Veterinary Medical Association (AVMA) to estimate your dog's age:

• The first year of a dog's life equals roughly 15 human years. 
• The second year of a dog's life equals roughly 9 human years.
• Each additional year equals roughly 4 or 5 human years.

So, why does the "1 dog year = 7 human years" methodology hold less weight?

Because, unlike the newly created formula, this does not take into account that different dog breeds age differently. Generally, smaller dogs live longer than larger dogs — so, for example, a seven-year-old Mastiff might be considered a senior dog, but the same would not necessarily be true for a seven-year-old French Bulldog. 

With this in mind, it may be helpful to break down the dog's lifespan in terms of size. Generally, one can divide dogs into four groups — small dogs under 20 pounds, medium-sized dogs weighing 20 to 50 pounds, large-sized dogs at 50 to 100 pounds, and the really big ones weighing over 100 pounds.

Here's a neat graph from the American Kennel Club (AKC) that can help you determine your dog's age in human years based on their size: 

Why is it Important to Know Your Dog's Age?

Knowing your dog's age is important for a variety of reasons. For one, it helps determine whether or not they are at risk of developing certain diseases or conditions. Plus, it can provide insight into their emotional and mental state as they age.  

Dogs age in a similar manner as people, but their lifespans are considerably shorter. You can watch out for many signs of aging in your dog, including changes in eating habits, sleeping patterns, and general activity levels. The most common sign is gray hair — it usually appears around the muzzle, on the ears and chest, or on paws. 

Though there is no guaranteed way to stop time from taking its toll on our furry friends, there are things you can do today to help them live a happier and healthier life. Consult your nearest vet today to learn more. 

Related Blog: Everything You Need to Know About Protecting Your Pet’s Heart 

Concluding Thoughts

One of the most confusing aspects of pet ownership can be figuring out how old your dog is. It is understandable why you might think this would be easy, especially since dogs age at about seven times the rate humans do, but it is not always clear whether you should be counting years or months (or even days). Don't worry! This guide to converting dog years to human years will help you understand exactly how old your dog actually is and also give you an estimate of how long he has left to live in both human years and his original dog years.

Cliffdale Animal Hospital: Experienced Vets You Can Rely On

Cliffdale Animal Hospital in Fayetteville, N.C., is home to a team of skilled veterinarians with years of experience treating a number of pet ailments. Bring your beloved four-legged companion to us, and we will make sure your pet is healthy no matter their age! Call (910) 487-5013 or fill out this form if you have any questions.