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

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

Bullmastiff vs Cane Corso: Vet-Reviewed Key Differences (With Pictures)

The Cane Corso and Bullmastiff are gentle giants and one cannot help but compare both their appearance and personalities. Other attributes that you...

Are There Health Benefits to Letting Your Pet Sleep with You? (Benefits and Risks)

Having a pet involves more than days spent playing, taking walks, or simply cuddling. At night, when the house is settling down, and...

Benadryl for Dogs: Our Vet Explains Safety & Effectiveness

A common antihistamine in households is Benadryl or diphenhydramine. It is a medication that pet parents readily have access to and quickly reach...

5 Reasons Why Dogs Run Away & How To Stop It

You could have the happiest dog living a life of luxury, and there’s still a chance that they end up running away. Even...

More related

11 Most Popular Dog Websites 2026: Resources for Every Dog Lover

Our resources as pet owners are continuously growing thanks to the expanding resources on the web. But have you ever wondered what all...

Can Dogs Eat Lunch Meats? Vet-Approved Facts & FAQ

Dogs enjoy eating meats and meat-flavored snacks. However, not all meat is safe for dogs to eat, including lunch meats. While it’s not...

Rin Tin Tin: The Story of an International Dog Star

The year was 1918 and one German Shepherd was making history. Rin Tin Tin, a dog forever etched in canine legacy, was one...

Bloodhound vs Coonhound: The Differences (With Info & Pictures)

Hunting dogs are extremely popular. In areas where outdoor culture is strong, hunting dogs regularly rank in the top five for most popular...

Keep reading

Dr. Marty Dog Food vs The Farmer’s Dog (2026 Comparison): Pros, Cons & What to Choose

Pet food has come a long way, with many brands, options, and ingredients claiming to be this or that. Pet food manufacturers go the extra mile with their marketing efforts, claiming their brand is complete, balanced, and wholesome for your...

Dogster_Dog Food Dr. Marty VS The Farmer_s Dog

Can Dogs Eat Scooby Snacks? Vet-Verified Nutrition Facts

When it comes to your dog eating Scooby Snacks, finding healthy snack alternatives is a wise plan, given that we can’t say for sure if the original product still exists. While there were once dog treats marketed as such, today,...

person holding dog treats on the jar

7 Best Dog Food Can Lids in 2026 – Reviews & Top Picks 

If your dog eats a wet food diet and you don’t use the whole can at once, the last thing you want is the leftovers stinking up your fridge! Instead of using cling film or aluminum foil every time, there...

ORE Pet Can Cover

Can Changing Dog Food Cause Vomiting? Vet-Reviewed Facts & Advice

I have a four-year-old Boxer who has a very strange thing happening. He is throwing up a foamy white discharge. He first threw up yellow......
Dog vomit in the living room on the floor

Can Dogs Eat Saffron Rice? Vet-Verified Facts & Safety Guide

Saffron rice is a tasty and savory dish, and dogs may be tempted to eat it. Many dogs enjoy the taste of rice and may see no problem with eating saffron rice. However, the issue with saffron rice is that...

Can Dogs Eat Saffron Rice

Can Dogs Drink Wine? Vet-Verified Risks & FAQ

If you enjoy relaxing with a glass of wine in the evenings, you might feel inclined to give your dog some. Their adorable begging as you sip the wine could make you question whether a small sip could do them...

Can Dogs Drink Wine

Dog Nutrition: 6 Vet-Approved Essential Nutrients They Need

Nutrition and a healthy diet play a significant role in a dog’s health and well-being. Dog owners must stay on top of their dogs’ nutritional intake and ensure that they’re eating a well-balanced diet that supports daily body functions. However,...

golden retriever dog eating food from feeding bowl

Can Dogs Eat Honeydew Melon? Vet-Verified Nutrition Facts & FAQ

Honeydew melon is a favorite treat to eat in the summer heat. But if your dog is trying to get a piece, you want to make sure it is safe. Can dogs eat honeydew? Yes, dogs can eat honeydew in...

Can Dogs Eat Honeydew Melon