How old is my dog? Dog years to human years (and more)

Updated 28/11/2023

The age-old question - how old is my dog - will be answered here! We used to always multiply a dog’s age by seven to get the answer. So if your dog is seven, they would be forty-nine in human years. However, it seems this calculation isn’t so accurate. It turns out that dogs mature a lot quicker than us mere humans, especially in their early years. So the first year of your fur baby’s life is actually more equal to a whopping fifteen human years! Read on to learn how to tell how old your dog is...

Clues to Look For

If you’ve adopted a puppy or dog but you’re in the dark about their history (and you're still scratching your head and asking yourself how old is my dog?), follow these clues... 

Teeth 

Your dog’s teeth are a great indicator of their overall age. This will depend on your dog and also on the kind of dental care they’ve had before you adopted them. 

Here’s a rough guide of their age based on their teeth:

• 8 weeks: baby teeth are in
• 7 months: permanent adult teeth are in 
• 3-5 years: teeth may have some tartar buildup and wear
• 5-10 years: teeth show more wear and potentially signs of disease
• 10-15 years: teeth are heavily worn with considerable tartar buildup. Older dogs may also experience some tooth loss.

Bear in mind, if your dog has had regular dental check ups and appropriate treatment such as scale and polish, they may not have any tartar present as they get older. 

Eyes 

Age-related changes can often be seen in the eyes. Conditions like iris atrophy and cataracts can start to occur the older your dog gets. However, these are not present in every older dog and there isn’t a typical age where it begins to happen. Cataracts, for example, can still develop in younger dogs that are genetically susceptible but generally, the older a dog is the more eye issues he/she may develop. 

Greying 

White or grey hairs around your dog’s muzzle can go a long way in deciphering their age. Typically, greying of the muzzle starts around the age of five, but some dogs may start getting their silver as early as two years old depending on their breed and genetics. 

Breed Type

When you’re trying to figure out your dog’s age it’s a good idea to keep in mind the varying degrees of life expectancy between different breeds. Generally, the bigger the dog the shorter their life expectancy. Giant breeds like Great Danes and St Bernards have an age expectancy of between 8-10 years, while small dogs like terriers and toy breeds typically have a much older lifespan of 13+. 

Arthritis

If your dog is experiencing joint pain or stiffness he or she may have arthritis. Arthritis is a joint condition that is typically associated with older age, so if your dog shows any lameness or tender points in their body it may be a clue as to their advanced age. However, it can be difficult to determine your dog’s age range solely based on whether they have arthritis symptoms as there are many breeds with congenital issues like hip dysplasia which is common in Labradors, for example. 

Blood profile

Your vet can do blood work that analyses your dog’s kidney, liver, pancreas and thyroid function, which may help estimate their age range. Kidney and thyroid diseases often develop as dogs get older, while a younger dog, unless genetically predisposed, would most likely not have any problems. 

How to Figure Out Your Dog’s Age

 For an easy and accurate way to estimate your dog’s age, you can follow the below method for small, medium and large dogs under 100 lbs.

• The first year of a dog’s life is equal to 15 human years. 
• The second year of a dog’s life is equal to nine human years.
• Each additional year is equal to about four or five human years.

So, why is this dog age calculation more accurate than the old ‘one dog year equals seven human years’ method?

Because it takes into account that not all dog breeds age the same way. As we mentioned above, smaller dogs tend to live longer than larger dogs, so while a seven-year-old Mastiff might be considered an oldie, the same isn’t true for a ten-year-old Jack Russell who might have another good 5+ years of life left and potentially more. 

Why do breeds age differently?

From research, scientists have confirmed that aside from giant breeds – small, medium, and large dogs age pretty similarly until they reach the age of 6. Then, bigger dog breeds start to age much faster. By seven years old, a small dog, like a Yorkshire Terrier, will be six human years younger than a large breed, like a Labrador. Why does this happen?

Ultimately, no one knows exactly why smaller dogs age slower and live longer than larger ones. According to the American Kennel Club, some researchers guess that it’s because larger dogs are affected by age-related diseases more quickly. Larger dogs tend to progress from puppyhood to adulthood a lot quicker, making abnormal cell growth, cancer and other diseases more likely to occur. Bigger breeds also tend to have more arthritis and hip dysplasia that may also shorten the length of their life. It’s for these reasons that using the old ‘one dog year equals seven human years’ method isn’t the best way to calculate your dog's age.

While the newer method we’ve shared is more accurate, your dog’s age is still a tricky number to nail down as age does not only depend on your dog’s size, but their breed and individual genetics as well. So to make answering how old is my dog a touch easier for you, find a rough reference guide below for small, medium, large and giant breeds on dog years to human years below.

Dog years to human years - a quick reference guide to small dogs (20lb or less)

How old is a 1 year old dog in human years?

A 1 year old dog is the equivalent to 15 human years old.

How old is a 2 year old dog in human years?

A 2 year old dog is the equivalent to 24 human years old.

How old is a 3 year old dog in human years?

A 3 year old dog is the equivalent to 28 human years old.

How old is a 4 year old dog in human years?

A 4 year old dog is the equivalent to 32 human years old.

How old is a 5 year old dog in human years?

A 5 year old dog is the equivalent to 36 human years old.

How old is a 6 year old dog in human years?

A 6 year old dog is the equivalent to 40 human years old.

How old is a 7 year old dog in human years?

A 7 year old dog is the equivalent to 44 human years old.

How old is an 8 year old dog in human years?

A 8 year old dog is the equivalent to 48 human years old.

How old is a 9 year old dog in human years?

A 9 year old dog is the equivalent to 52 human years old.

How old is a 10 year old dog in human years?

A 10 year old dog is the equivalent to 56 human years old.

How old is an 11 year old dog in human years?

A 11 year old dog is the equivalent to 60 human years old.

How old is a 12 year old dog in human years?

A 12 year old dog is the equivalent to 64 human years old.

How old is a 13 year old dog in human years?

A 13 year old dog is the equivalent to 68 human years old.

How old is a 14 year old dog in human years?

A 14 year old dog is the equivalent to 72 human years old.

How old is a 15 year old dog in human years?

A 15 year old dog is the equivalent to 76 human years old.

How old is a 16 year old dog in human years?

A 16 year old dog is the equivalent to 80 human years old.

Dog years to human years - a quick reference guide to medium dogs (21-50 lbs)

How old is a 1 year old dog in human years?

A 1 year old dog is the equivalent to 15 human years old.

How old is a 2 year old dog in human years?

A 2 year old dog is the equivalent to 24 human years old.

How old is a 3 year old dog in human years?

A 3 year old dog is the equivalent to 28 human years old.

How old is a 4 year old dog in human years?

A 4 year old dog is the equivalent to 32 human years old.

How old is a 5 year old dog in human years?

A 5 year old dog is the equivalent to 36 human years old.

How old is a 6 year old dog in human years?

A 6 year old dog is the equivalent to 42 human years old.

How old is a 7 year old dog in human years?

A 7 year old dog is the equivalent to 47 human years old.

How old is an 8 year old dog in human years?

A 8 year old dog is the equivalent to 51 human years old.

How old is a 9 year old dog in human years?

A 9 year old dog is the equivalent to 56 human years old.

How old is a 10 year old dog in human years?

A 10 year old dog is the equivalent to 60 human years old.

How old is an 11 year old dog in human years?

A 11 year old dog is the equivalent to 65 human years old.

How old is a 12 year old dog in human years?

A 12 year old dog is the equivalent to 69 human years old.

How old is a 13 year old dog in human years?

A 13 year old dog is the equivalent to 74 human years old.

How old is a 14 year old dog in human years?

A 14 year old dog is the equivalent to 78 human years old.

How old is a 15 year old dog in human years?

A 15 year old dog is the equivalent to 83 human years old.

How old is a 16 year old dog in human years?

A 16 year old dog is the equivalent to 87 human years old.

Dog years to human years - a quick reference guide to large dogs (51-100 lbs)

How old is a 1 year old dog in human years?

A 1 year old dog is the equivalent to 15 human years old.

How old is a 2 year old dog in human years?

A 2 year old dog is the equivalent to 24 human years old.

How old is a 3 year old dog in human years?

A 3 year old dog is the equivalent to 28 human years old.

How old is a 4 year old dog in human years?

A 4 year old dog is the equivalent to 32 human years old.

How old is a 5 year old dog in human years?

A 5 year old dog is the equivalent to 36 human years old.

How old is a 6 year old dog in human years?

A 6 year old dog is the equivalent to 45 human years old.

How old is a 7 year old dog in human years?

A 7 year old dog is the equivalent to 50 human years old.

How old is an 8 year old dog in human years?

A 8 year old dog is the equivalent to 55 human years old.

How old is a 9 year old dog in human years?

A 9 year old dog is the equivalent to 61 human years old.

How old is a 10 year old dog in human years?

A 10 year old dog is the equivalent to 66 human years old.

How old is an 11 year old dog in human years?

A 11 year old dog is the equivalent to 72 human years old.

How old is a 12 year old dog in human years?

A 12 year old dog is the equivalent to 77 human years old.

How old is a 13 year old dog in human years?

A 13 year old dog is the equivalent to 82 human years old.

How old is a 14 year old dog in human years?

A 14 year old dog is the equivalent to 88 human years old.

How old is a 15 year old dog in human years?

A 15 year old dog is the equivalent to 93 human years old.

How old is a 16 year old dog in human years?

A 16 year old dog is the equivalent to 99 human years old.

Dog years to human years - a quick reference guide to giant dogs (100 lbs+)

How old is a 1 year old dog in human years?

A 1 year old dog is the equivalent to 12 human years old.

How old is a 2 year old dog in human years?

A 2 year old dog is the equivalent to 22 human years old.

How old is a 3 year old dog in human years?

A 3 year old dog is the equivalent to 31 human years old.

How old is a 4 year old dog in human years?

A 4 year old dog is the equivalent to 38 human years old.

How old is a 5 year old dog in human years?

A 5 year old dog is the equivalent to 45 human years old.

How old is a 6 year old dog in human years?

A 6 year old dog is the equivalent to 49 human years old.

How old is a 7 year old dog in human years?

A 7 year old dog is the equivalent to 56 human years old.

How old is an 8 year old dog in human years?

A 8 year old dog is the equivalent to 64 human years old.

How old is a 9 year old dog in human years?

A 9 year old dog is the equivalent to 71 human years old.

How old is a 10 year old dog in human years?

A 10 year old dog is the equivalent to 79 human years old.

How old is an 11 year old dog in human years?

A 11 year old dog is the equivalent to 86 human years old.

How old is a 12 year old dog in human years?

A 12 year old dog is the equivalent to 93 human years old.

How old is a 13 year old dog in human years?

A 13 year old dog is the equivalent to 100 human years old.

How old is a 14 year old dog in human years?

A 14 year old dog is the equivalent to 107 human years old.

How old is a 15 year old dog in human years?

A 15 year old dog is the equivalent to 114 human years old.

How old is a 16 year old dog in human years?

A 16 year old dog is the equivalent to 121 human years old.

Why does your dog’s age matter? 

Using a dog age calculator to estimate your dog’s age in human years is a fun way to learn more about your beloved pet. It’s also important because ultimately finding out how old your dog is and how they’re aging allows you to care for them well and help give them the best life possible.

Keep in mind, if you have a larger dog, you’ll want to start looking for signs of aging around five or six, whereas smaller dog owners might not see any real signs of your dog slowing down until 8/9 years of age. Regardless, once your dog reaches their senior years, you’ll want to monitor their behavior, activity level, and eating habits to see if they change and act accordingly to their needs. For example, if they start tiring on their walk, you might want to consider shortening the length. If they have to have some teeth removed, then ask your vet for advice on what food is best for them. 

In general, a healthy diet and weight, physical activity, and regular check-ups at the vet will all help prolong your dog’s life expectancy. Your dog deserves the best care possible no matter how old they are – this is why we offer a wide variety of different sitters with all types of experience to help care for your dogs(s). 

Meet our veterinary expert, Emma

This article has been checked by veterinarian Emma Chandley, BVetMed MRCVS PGCertSAS. Emma graduated from the Royal Vet College in London in 2011. She has a keen interest in surgery and went on to do a postgraduate certificate in small animal surgery and was then awarded advanced practitioner status in the same discipline.

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