Dog Years to Human Years: Your Canine's Lifespan Explained

Whether you've got a puppy or an older pooch in your household, it is natural to wonder how to translate their age from dog years to human years.

Historically, there have been various myths which claim to have the answer to this equation.

One of these suggests that to find out a dog's age, you simply multiply it by seven to reveal its human equivalent. But, how accurate is this really?

When asked about the effectiveness of this method, Director of Veterinary Medicine for the Animal Medical Center of Mid-America (AMCMA), Dr. Travis Arndt told Newsweek: "There isn't really a one-size-fits-all answer."

Newsweek consulted canine experts to find out the best way to estimate your dog's age, what life stages they go through and how to care for an elderly pet.

What Are Dog Years Compared to Human Years?

Dr. Travis Arndt said the seven years method is "probably inaccurate and outdated," in most cases. He explained that there are various factors that contribute to a dog's rate of aging, so working out how to convert dog years to human years is more complicated.

He continued: "In reality, the biggest factor is a dog's size. Smaller dogs tend to live longer than larger dogs, so the comparison of "dog years" to regular years will change depending on the dog's weight and breed."

"Pets are also statistically now living longer than ever before due to advancements in veterinary medicine and increased awareness of health factors for pet owners."

Arndt said, on average, the first year of a medium-sized dog's life is equivalent to about 15 human years, while the second is more like nine human years, and every year after that is equivalent to about five human years.

Researchers at the University of California San Diego School of Medicine did a study into the aging of dogs and suggested that, after a dog turns seven-years-old, the rate of aging decreases, meaning Arndt's suggested schedule of development could make sense.

The Stages in a Dog's Life Explained

As Arndt mentioned, it is certainly not a case of one size fits all, and different breeds tend to mature out of puppyhood at different times to those which are larger.

Size is key to helping understand the life stages of dogs, but according to veterinary expert for Pumpkin Pet Insurance, Dr. Sarah Wooten, a simplified way of looking at the stages of a dog's life is to split them into two categories: puppy and adult.

Stock image of dog with owner
A stock image of dog being held by its owner. Getty Images

She told Newsweek: "In general, dogs are considered puppies until they are one year of age, and then considered adults thereafter. However, that's also not completely accurate.

"Small breed dogs mature out of puppyhood and become fully grown adult dogs between 7-10 months of age, medium breed dogs reach adulthood around 12 months of age, large breed dogs stop growing between 12-18 months of age, and giant breeds, like Mastiffs or Great Danes, can continue to grow until 2 years of age."

However, she gave an idea of the different periods of a dog's life, beginning with the neonatal period and early puppyhood, and ending with a mature and senior adult dog.

Here are the different dog stages, as explained by Dr. Wooten:

  • Neonatal period (up to two weeks)
  • Early puppyhood - (two to six weeks)
  • Critical Socialization Period (six-16 weeks, varies with individuals)
  • Juvenile (three to six months)
  • Adolescence (six to 12 months)
  • Young Adulthood (one to three or four years)
  • Mature Adult (four years)
  • Senior (six years onward)

With all the stages, the exact times at which they occur change depending on the breed and size of the dog.

Due to the nonlinear way in which dog years and human years correlate, it is difficult to match these up exactly with a human growth rate.

However, a one-year-old dog is considered to be similar in age to a human in their teen years. A six-year-old dog, following the aging schedule mentioned above, would be closer to their mid-40s in human terms.

How To Care For an Elderly Dog

In the same way that dogs' ages can really vary depending on their breed and size, similarly, their life expectancy can be anything from seven years for giant breeds, to more like 15 years for small breeds.

It is hugely important to care for your dog in its later stages of life, as this is when health issues can flare up.

CEO and founder of puppy training school Rebarkable, Ali Smith, said a key thing to remember with older dogs is to take things at their pace, and be aware of their needs.

Stock image of dog with owner
A stock image of dog walking with its owner. Getty Images

She told Newsweek: "If they can't make the walks, that's ok. Some days they will, and other days they won't."

"Look out for signs of subtle pain. Dogs tend to hide their pain very well, so look for signs like lameness, stiffness after resting, licking or scratching at a certain area and snappiness. And give them the best support."

Some of the support she suggested was regular vet trips, orthopaedic beds and less jumping, for example using ramps to help them get in and out of the car.

She also said to make sure your dogs get proper exercise, adequate sleep and a healthy diet for their whole lives, but to watch for issues like dementia as they get older.

Owner of the Healthy Dog Expo, Lauren Coger, told Newsweek that the key is to be proactive. She encourages dog owners to make sure they research issues that could befall dogs in their older age.

She added: "Start with an assessment of your dog, and their health risks, and address them from a young age. For example, if you have a big Labrador prone to hip dysplasia? Start joint support supplements, daily exercise, and weight monitoring from the time they enter adolescence."

"Have a breed prone to heart disease? Get a yearly check up with a veterinary cardiologist, so you can catch any problem early. The best outcomes come from prevention and early detection."

Labrador puppy and older dog
A Labrador Retriever puppy and a grown Labrador Retriever, at an American Kennel Club press conference January 30, 2013 in New York. STAN HONDA/AFP/Associated Press, Getty Images