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’s Sleeping Habits Have Changed! (May 18, 2026)

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

The Crate Setup Most Dog Owners Get Wrong (And How To Fix It!)

Most people assume that if their dog hates the crate, the crate is the problem. So they try a bigger one, a different...

1,500 Beagles Rescued from Wisconsin Lab Farm – Here’s Where They’re Going

You may remember that a few weeks ago, we reported on a tense situation at Ridglan Farms, Wisconsin, a facility infamous for housing...

Dogster’s Weekly Photo Contest Winners: Window Watchers (May 11, 2026)

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

More related

Can Dogs Eat Ginger Snaps? Vet-Verified Facts & Explanation

Ginger snaps are a spiced cookie that’s synonymous with the holiday season. They’re slightly sweet without being too overpowering, and deliciously crunchy. While...

Can Dogs Have Tourettes? Vet-Verified Facts & Info

Humans and dogs have a lot more in common than you may realize. After all, we all share 84% of our DNA. We...

Border Collie Grooming: 15 Vet-Approved Tips

Did you know Queen Victoria loved Border Collies? In fact, she became an active enthusiast in the 1860s. If you have a Border...

Can You Change Your Dog’s Name? Vet-Reviewed Pros, Cons & Tips

One topic that almost always sparks debate among dog parents and dog lovers is if changing a dog’s name is an appropriate thing...

Keep reading

4health vs Purina Pro Plan Dog Food: 2026 Comparison, Pros & Cons

If you own a dog, you already know the struggle of picking a good dog food. However, as you continue to look around at different options, you may begin to question your choice. Are the more expensive brands better? Is...

Dogster_Dog Food 4health vs Purina Pro Plan

Pedigree Dog Food Review 2026: Recalls, Pros & Cons

Review Summary Pedigree is a well-known dog food brand that’s been around for decades. You can find recipes for dogs of all life stages sold by Pedigree. The main appeal of Pedigree dog food is its affordability and accessibility, as...

Dogster_Pedigree Dog Food Review

What Is Fish Meal in Dog Food? Vet-Approved Safety Facts & FAQ

If you’re a dog owner who likes to read pet food labels, you’ll probably find quite a few unfamiliar ingredients listed. One such product is fish meal, commonly found in allergy-friendly diets. But what is fish meal in dog food,...

Wet and dry pet food made of natural ingredients

Can Dogs Eat Yogurt? Vet-Verified Nutrition Facts & FAQ

Yogurt is one of the rare treats that blends a delicious flavor with potential health benefits. If you’re a diehard fan of the tasty dairy delight, you’ve probably wondered whether your pets could enjoy it as much as you do....

Can Dogs Eat Yogurt

How to Choose the Best Vegan Dog Food in 2026 – Complete Guide

Adopting a vegan lifestyle is a pretty major commitment, but with the increased range of plant-based products on the market, it has become easier to do than even five or ten years ago. For some, it means keeping everything in...

vegan dog food on pet bowl

How Much to Feed a German Shepherd: Vet-Approved Guide

Do you have a German Shepherd? If so, you’re probably wondering how much food to feed him. It can be tricky to figure out the right amount, especially since puppies and adults have different nutritional needs. In this blog post,...

german shepherd dog lying near food bowl

Can Dogs Eat Licorice? Vet-Verified Nutrition Facts & Info

Our pets can eat all sorts of goodies that we can prepare from the comfort of our own kitchens. However, when it comes to sweets, it isn’t always the best idea to share with our four-legged friends. Licorice is not...

twizzlers licorice candies

Ethoxyquin in Dog Food: Why Is It Controversial? Vet-Verified Facts

Dog owners, brace yourselves! The food your beloved canine companion eats on a daily basis might contain a controversial ingredient – ethoxyquin. This synthetic antioxidant, commonly used as a preservative in dog food, has sparked heated debates among pet enthusiasts...

man checking dog food label

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