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How To Calculate Dog Years To Human Years

Are you trying to figure out how old your dog is in human years? Veterinarian Hannah Godfrey looks at a new, more accurate way to calculate their age and why it's important to know the associated health risks that come with each phase of life.

Dr. Hannah Godfrey

Last Updated: March 3, 2023 | 7 min read

Dog with glasses on next to calculator

This article was written by a veterinarian, but it should not serve as a substitute for a discussion with a trained professional. If your dog ate turkey and is reacting adversely, contact your local veterinarian immediately.

One of life’s most unfair realities is that our canine companions don’t live as long as their loving human family members.

Dogs bring so many positives to our lives in the form of friendship, affection, and motivation to get active outdoors. Many people struggling with loneliness or poor mental health provide a reason to get out of bed and create smiles and laughter with their funny antics and waggy tails.

People have been comparing dogs’ ages with humans for years. After all, as a pet parent, it’s much harder to accept that your furry friend’s life span is a measly 12 to 15 years when humans might live more than five times as long. So, how can you translate your dog’s age into human terms?

Dog Years vs. Human Years

Dog with birthday party hat and decor
Want to throw your dog a birthday party but don’t know their birthday? Use this guide to determine their age.

How do you calculate a dog’s age, and how can you compare their age to your own? There are two methods and a chart below to determine their age in human years.

The Traditional Way

Traditionally, we used a simple conversion to turn a dog’s age into human years. This method involved multiplying each year of their age by seven. This process allowed pet parents to understand that their dog would be the equivalent age of a 70-year-old human at ten years of age.

Although it helped dog owners to acknowledge their fur-baby’s senior years, it did have some shortcomings. The problem is that the time frame for the development of children and teenagers does not match well with puppies and adolescent dogs.

For example, according to this method, by the end of their first year, your dog would be seven in human years. However, puppies start to mature quicker than this and are considered adolescents by around a year old. So, the seven-year rule can be modified to better reflect your dog’s development.

A New, Better Way

Although there is no perfect way to transform doggy years into a human’s age, there is a new, better way than using the seven-year method. Your dog’s first year should be deemed equivalent to 15 human years, while the second year is nine. The third year is six, and each year following this is considered to be around five human years, as shown in the table below:

Dog Age Chart (based on new methodology)

This chart shows the basic calculations with the new method for determining a dog’s age, but please note that it can vary based on breed makeup and size.

Dog age (years)
Equivalent human age (years)

Dog Breed Size

The above system gives a good ballpark figure when calculating a pup’s age. However, it works best for a medium-breed dog. As a rule, large and giant breed dogs don’t live as long as small breeds. Therefore, if you’re applying the system to your large-breed dog, you should use six human years per year rather than five. For a small-breed dog, you should use four per year.

Why Is It Helpful to Know Your Dog’s Age?

Dog in various stages of life
There are tangible benefits to understanding a dog’s life stage.

From training and behavior concerns to ensuring their environment and lifestyle needs are met. A vital part of pet ownership is acknowledging how old your dog is.


Establishing good training is an integral part of being a responsible pet parent. However, your goals and expectations of training vary drastically depending on your canine companion’s age. For example, as a very young puppy, you might want to focus on house training and basic commands. As your pup gets older, training might focus on leash walking, some simple tricks, and a bit of recall.

It’s important not to overwhelm a young puppy with high-level training too early. However, it’s a great idea to establish good recall, leash walking, and sit and stay commands before the chaos of adolescence. Older dogs can become very set in their ways, so training might be trickier and could even require help from a behaviorist. Knowing how old (or young) your dog is helps you make sure that your activity is age-appropriate.

Behavior Issues

Knowing your puppy or dog’s age can also help determine whether you need some extra help with their behavior. For example, it can be pretty normal for a young pup to mouth and nip, and as long as the behavior isn’t encouraged, they should grow out of it. However, an older dog growling or biting is much more concerning. Therefore, it would be good to get input from a veterinarian or specialist behaviorist in this situation. So, better knowledge of your pet’s age can help you decide which behaviors can be safely ignored and which can’t.


Tailoring your dog’s exercise routine to their life stage is essential. A puppy needs controlled exercise to not put too much strain on their bones and joints while they are still growing. Similarly, older dogs might have arthritis, back pain, or other ailments, so that they might need an appropriately gentle exercise plan. On the other hand, adolescent and young adult dogs can have limitless energy. A large amount of exercise and stimulation is needed to keep them from gaining weight or developing behavior issues.


Just like when we get older, senior dogs need (and deserve) a bit of comfort. Their joints and muscles might be aching and sore, and they might not find it so easy to get up and down the stairs. So, a padded bed and making sure they can easily reach food and water and get outside to go to the toilet helps your golden oldie enjoy life.


You might have noticed that various dog food brands have unique formulations for each life stage. But is puppy food that different from adult and senior diets? And are they all really necessary? The truth is that your dog’s nutritional needs vary dramatically depending on their age.

As a puppy, while they are growing quickly, they need a high-calorie, high protein diet with plenty of vitamins and minerals. An adult dog still requires these things, but less of them. If you feed your adult dog puppy food, they would probably pile on the pounds. Senior dog foods often contain reduced calories to reflect their less active lifestyle. They might have reduced protein to protect your canine’s kidneys and extra ingredients like fish oils to keep their skin, coat, and joints healthy.

Health Checks

There are times in your dog’s life when they might only need to see the veterinarian once a year for a checkup and booster shots. On the other hand, there’s likely to be times when your dog is a frequent veterinary visitor. Once you know your dog’s age, you can determine the times for scheduling regular checkups.

Puppies visit the veterinary clinic a few times in their early years for vaccinations and health checks, giving your veterinarian ample opportunity to check all is well. But don’t forget that older dogs often need regular health checks too, helping spot the signs of illness or arthritis early.

Pet Insurance

Pet insurance is a helpful tool to help you manage and plan for unexpected high vet bills in times of emergency. The younger your dog is when you sign them up, the fewer pre-existing conditions will be excluded from coverage. So, if you have a young pup, now would be an excellent time to see if pet insurance would be a good choice for you and your furry friend.

What If You Don’t Know How Old Your Dog Is?

Inspecting a dog's teeth
The condition of the teeth is one major clue in estimating a dog’s age.

It’s all well and good to try to work out their human age, but it can be hard to determine a good guess with a rescued or rehomed dog. But, if you look at them closely, you might find some clues that hint at their age—failing that, you can always ask your veterinarian to help you estimate their age.

Baby or Adult Teeth

Just like humans, dogs have temporary baby teeth before their adult teeth. These baby teeth appear at about eight weeks and turn into adult teeth by around six months, so these milestones can help you work out your pup’s age. Baby teeth are much smaller and pointier than adult teeth, so you should be able to spot the difference. As your puppy transitions from puppy to adult teeth, they will go through teething. And like human babies, teething toys may help.

If you look in your dog’s mouth and see larger, more rounded, adult teeth, you know your dog is older than six months. If they are close to 6 months old rather than older, you might even spot a mixture of adult and baby teeth.

Beware, though, some dogs retain their temporary canine teeth and end up with one adult and one baby canine tooth alongside each other. You might assume that this means they are young, but if a veterinarian doesn’t remove the tooth, they can stay until later in life.

Teeth Condition

If their teeth are white and smooth, with no evidence of tartar and no missing teeth, they’re probably a young adult dog. In contrast, senior dogs may have discolored, tarter-covered teeth, and they might even be missing or wobbly. Older dogs might also have smelly breath.

Gray Hairs

It’s not just people who go gray. Some dogs do too. Hair around the face is particularly prone to going gray. Therefore, if you notice your dog looking more silver or white around the muzzle, it might be a little older than you thought. However, looking for gray hairs isn’t a foolproof method because some dogs have gray coloring throughout their whole life, while others don’t seem to go very gray at all.


If your dog isn’t looking as agile as they used to, or they take a little while to get going after a lie-down, they might be getting on a bit in years. However, it’s important not to chalk up stiffness or joint pain as a natural part of aging. Arthritis can be excruciating, and your veterinarian can recommend treatments to keep your dog more comfortable.

Warts and Skin Tags

Although no lumps and bumps should ever be ignored, some skin lumps can appear as your canine companion gets older. Skin tags and warts are reasonably common and often benign but should always be checked by your veterinarian if they are something more sinister.

Cloudy Eyes

As your perfect pooch gets older, you might notice their eyes start to look more cloudy. This is called nuclear sclerosis and is part of the aging process. Thankfully, it shouldn’t affect your dog’s sight, but you should seek veterinary advice because it can look similar to a cataract.

Final Thoughts

Old dog sleeping
A healthy dog is a happy dog, no matter its age.

Many of us remember the outdated formula that each dog year is equivalent to seven human years, but the new method of calculating your dog’s age is more accurate and can be adjusted by breed.

Even if your dog is a rescue, you and your veterinarian can do some detective work to estimate their approximate age. Once you know your dog’s life stage, you can ensure that their lifestyle, routine, and environment is tailored to keep them as happy, healthy, and comfortable as possible.

Measuring cup, bowl with dry food and toys for dogs on the orange background

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