Get

In Your Inbox

Dogster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

How Old Is 13 in Dog Years? Vet-Approved Guide to Each Size of Dog

Share

close up senior boxer dog

You’ve probably wondered before how old your canine companion is in human years rather than dog years. You’ve probably also tried to figure it out using the “one year in a dog’s life equals seven human years” equation. But it turns out that the 7:1 ratio of figuring out the human age of a dog isn’t exactly correct. The theory of why this method came about is that people saw dogs living to be about 10 years old and decided that if humans lived to be about 70 years old, then that must mean a single year of a dog’s life was roughly seven human years.

We know a bit more about how dogs age these days, though, and it seems the 7:1 ratio is just a bit off. In fact, there are several things that factor into how old a dog would be in human years, including the size and breed of the pup. So, how do you figure out your pet’s age?

Take a dog who is 13 years old; how old is the dog age of 13 in human years? Well, a 13-year-old dog could be anywhere from 68 to 100 years old in human years! Here’s a closer look at how it all works.

divider dog paws 3 oct 2024

A Guide to the Ages of Dogs According to Size

You’re welcome to use our images, but we require you link directly to this site for credit (ex. Image from Dogster)

The first thing to know is how exactly age is calculated for canines now. The American Veterinary Medical Association has determined that the first year of life for dogs is roughly 12 to 15 human years, while the second year is about 9 to 10 human years. After that, each year of a dog’s life is approximately 4 to 5 human years. But the numbers vary according to a dog’s size.

Small Breeds

senior merle dachshund running inside a dog boarding facility
Image By: Ryan Brix, Shutterstock

For whatever reason (and no one is quite sure why), smaller dogs live longer than larger ones. One theory is that larger dog breeds experience faster growth, which can lead to a higher likelihood of cancer, resulting in earlier deaths. Whatever the reason for this phenomenon, it means that for a small dog, the first year of their life will be around 15 human years. By the second year of life, they will be 24 in human years, and by the third, they will be 28 human years. So, a 13-year-old small breed dog will be about 68 years old in human years. Definitely a senior, but on the younger side!

Medium Breeds

Senior cocker spaniel dog lying on grass
Image Credit: Angyalosi Beata, Shutterstock

Medium breed dogs are about the same as small breeds in that the first three years of their lives also end up being 15, 24, and 28 in human years. However, around the age of six, medium-sized dogs start aging just a bit more quickly than smaller pups. This means that by age thirteen, a medium-breed canine would be about 74 years old in human years.

Large Breeds

an old senior dog tilting its head outdoors
Image Credit: Suchavadee, Shutterstock

As we said before, larger breeds age faster than smaller canines. But like with medium-sized dogs, large breeds are the same in human years as small and medium breeds until the age of six. This is when larger breeds really begin to age more quickly, so by the time a pup is thirteen, they are about 82 in human years.

Giant Breeds

senior great dane dog up close
Image Credit: apolda, Shutterstock

If a large breed dog grows and ages faster than smaller canines, then giant breeds are the fastest of them all. They start off a bit younger than their counterparts, though, with the first year of a giant breed dog’s life equaling about 12 human years. Their second year is equal to only about 22 in human years. However, they begin to age more quickly around three years old, which ends up being equivalent to about 31 in human years. So, by the time they are thirteen in dog years, they’re roughly 100 in human years!

dogster face divider

How Can I Help My Dog Live a Longer Life?

There will always be a limit to how long your favorite canine will live, but there are ways you can help them live their longest, happiest, healthiest life. Here’s a look at what you can do to help your pup.

old golden retriever dog
Image Credit: marcinm111, Shutterstock

Diet

A healthy diet consisting of a quality dog food that meets all your pup’s nutritional needs will go far in keeping them healthy. You may want to look for breed-specific, size-specific, or lifestage-specific food to be sure your pet is getting all the proper nutrients. You should also ensure that you’re watching your dog’s weight; many breeds are prone to extra weight gain, which can cause health issues later on. Every dog is unique in their nutritional needs, so we recommend reaching out to a vet for advice.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's our online service where you can talk to a vet online and get the personalized advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content Savings V1

Healthcare

Keeping up with your pet’s healthcare is also essential. Ensuring your pup is getting routine vaccinations as needed will help keep them healthy while ensuring they are receiving medication that fights ticks and fleas will help prevent disease. And don’t skip out on regular vet visits; often, this is when a vet will catch something early enough to be able to remedy the issue!

Exercise

The adage “exercise does a body good” applies to dogs just as much as it does to humans! Your pup will need daily exercise (how much will vary, depending upon their size, age, and breed), so be sure you’re getting those walks in each day. Also, include plenty of playtime and other physical activities to keep your pup in good shape.

Senior golden retriver dog swimming with vest ,rehabilitation
Image Credit: Wasitt Hemwarapornchai, Shutterstock

Environment

The environment a dog is living in is equally essential to keeping them healthy. Their environment should involve plenty of love and affection, as well as meet their physical needs (like having enough toys or a dog bed to sleep on). Canines should also be provided with mental stimulation to keep them from becoming bored and unhappy, so invest in some puzzle toys or games that keep them on their toes!

Spay/Neuter

You may think that having your dog spayed or neutered is merely to prevent unwanted puppies, but a study by the University of Georgia examining 40,139 death records over a 20-year period concluded that spayed or neutered dogs usually live longer than intact dogs. Sterilized dogs had an average lifespan of 9.4 years, while intact dogs lived for 7.9 years on average.

divider dog paws 3 oct 2024

Conclusion

The belief that a single dog year equals seven human years is a long-held one, but how a dog ages is a bit more complicated. Dogs age at different rates depending on their size, so while a small breed dog may be only around 68 in human years by the time they reach the age of thirteen, a giant breed dog will be nearly 100 human years old at the same dog age! How dogs age is still being researched, so we’re liable to learn even more about the process and how it compares to human aging in the future.

In the meantime, you can help your pet live their longest, fullest life by ensuring they are eating well, exercising regularly, having routine vet check-ups, living in a happy environment, and discuss having them spayed or neutered with your vet.

See Also: 


Featured Image Credit: Holly Michele, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything dog

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Dogster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Ask Dr. Paola- Help! My Dog Gets Reoccurring UTIs (March 9, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

DIY Repellents for the Dog Who Thinks Everywhere Is His Toilet

Dog urine and everything nice have a complicated relationship. One thrives, the other suffers, and if you’re reading this, you already know which...

Dogster’s Weekly Photo Contest Winners: I Dig, Therefore I Am (March 5, 2026)

Every week our team gets the privilege of sorting through our readers photos to choose what dogs will win this weeks contest! See...

Ways to Stop Dog Boredom Before It Destroys Your House

Your dog is staring at you. They’ve paced between the door and the couch. They’ve sighed dramatically from their bed. The message is...

More related

Top 8 Dog-Friendly Beaches in Nevada You Can Visit in 2026

Spending a day at the beach is a fun and exciting pastime that is even more fun when you share the day with...

Easy Dog Treat Recipe: Mini Turkey Sliders (Vet-Approved)

The ingredients for this mini turkey slider dog recipe are likely the same ones you use for your own burgers. With your dog...

12 Indoor Dog Games to Play When You’re Stuck Inside

There’s nothing worse than being stuck indoors, especially when you have a dog to keep entertained. Although it’s not ideal for the day-to-day,...

How Intelligent Are Dogs? Here’s What Science Says

Interacting with your dog daily helps you become familiar with their behavior, and most of the time, our dogs leave us in awe...

Keep reading

8 Best Hydrolyzed Dog Foods in 2026 – Reviews & Top Picks

Owners are becoming more discerning about the ingredients and preparation of their pet’s food. Many times, there are products that we have never heard of and processes that we do not understand. One thing is for sure, however: When it...

miniature schnauzer dog eating on the sofa

Is Lamb Dog Food Good for Dogs? Vet-Reviewed Benefits & FAQ

There are a host of dog foods out there to choose from when it comes to feeding your dog and many different meat options available to tempt your pet’s palate. While a good majority of dog foods will contain chicken,...

dachshund dog eating from elevated bowl

Can Dogs Eat Pastrami? Vet-Reviewed Dietary Guidance

As dog owners, we know that we need to be careful when giving our dogs little treats from our plates. Human foods can be risky for dogs because not everything that we enjoy eating is safe for them. If eating...

Can Dogs Eat_Pastrami

Diamond Puppy Formula Dog Food Review 2026: Recalls, Pros & Cons

Diamond Pet Foods is a private company based out of Meta, Missouri. It began as a family-owned business in 1970 with brothers-in-law Gary Schell and Richard Kampeter at the helm. It prides itself on its nutritional integrity and quality assurance....

Dogster_Diamond Puppy Formula Dog Food Review

Can Dogs Eat Pigs’ Feet? Vet-Approved Facts & FAQ

Dogs are glad to try any meaty snack you wave in their faces, but it can be tricky to tell what exactly they can and can’t eat. For instance, can dogs eat pigs’ feet? Yes, dogs can eat pigs’ feet,...

Can Dogs Eat Pigs’ Feet

How Long Does It Take for a Dog to Digest Food? Vet-Approved Digestive System Basics

We all know that what we feed our dogs—and how they digest it—plays a key role in their overall health. If you’re wondering how long it takes for a dog to digest their food, unfortunately, the answer is not a...

french bulldog eating or drinking from a bowl

What to Do With Leftover Dog Food? 6 Great Ideas

No one wants to deal with leftover dog food. Perhaps your dog has passed away, or maybe your pet just doesn’t like the type of food you bought. Most people don’t buy more food than their dogs can typically eat,...

Open canned pet food

How Long Can Wet Dog Food Sit Out Until It Goes Bad? Vet-Approved Facts & FAQ

All pet food can only sit out for a limited amount of time before it starts to spoil. The time frame will vary depending on the type of food, as well as the ambient conditions. All dog food can sit...

Border collie holding food bowl

Love Dogs? So Do We! Join the Dogster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Dogster Email Newsletter