Dog years to human years

The primary or first year of a dog’s life is the equivalent to 15 human years. The second year of a dog’s life is equivalent to around nine human years. Each additional year is equivalent to around four or five human years.

Size and breed also play a role. Smaller dogs tend to live longer than larger ones, but they may mature more quickly in the first few years of life. A huge pup might age more slowly at first, but be nearing middle age at 5. Tiny and toy breeds don’t become “seniors” until around age 10. Medium-sized pooches are somewhere in the middle on both counts.

How do I calculate my dog’s age in human years?

If you’re looking to calculate your dog’s age in human years more accurately, you can use a new formula created by researchers at the University Of California San Diego School Of Medicine.

These researchers studied the way human and dog DNA changes over time looking at patterns called methyl groups in humans and Labrador Retrievers. From this research, they concluded that you can calculate a dog’s age to human years by multiplying the natural logarithm of the dog’s age by 16 and adding 31. Their formula looks like this: (human_age = 16ln (dog_age) + 31). As you can see, this formula is pretty complex, so it can be useful to plug in your dog’s age to an automatic calculator programmed with this formula.


The easy way to calculate a dog’s age is to take 1 dog year and multiple it by 7 years. This is based on an assumption that dogs live to about 10 and humans live to about 70, on average.

For example, a dog which is 5 years old is 35 “human years.” This isn’t a bad way to go from a health perspective because it helps us humans realize that our dogs aren’t the same as children.

As pets get older, they need extra care and attention. Small dogs are generally considered “senior” at seven years of age. Larger breeds are often senior when they are 5 to 6 years of age. Be aware of arthritis and related discomfort or irritability, weight control, sight and hearing issues, and any changes in behavior or activity that could indicate more serious issues.

Visit your vet for exams regularly; adjustments can be made to give your pets a more comfortable, longer, healthier life.

2019 Epigenetic Clock Study

A 2019 study by researchers at the University of California San Diego put forth a new method for calculating dog age, based on changes made to human and dog DNA over time. In both species, methyl groups are added to DNA molecules throughout aging, altering DNA activity without altering the DNA itself. As a result, DNA methylation has been used by scientists to study aging in humans through an “epigenetic clock.”

The research team performed targeted DNA sequencing in 104 Labrador Retrievers spanning a 16 year age range, in an attempt to compare dogs’ epigenetic clocks to those of humans. The results allowed them to derive a formula for adjusting dogs’ ages to “human years”, by multiplying the natural logarithm of the dog’s age by 16 and adding 31 (human_age = 16ln(dog_age) + 31). This natural logarithm calculator can help.

As the study included just a single breed, your own dog’s “human age” based on this formula may not quite match up. It’s known that different breeds age differently, so the UCSD formula may lack enough variables for conclusive results. Regardless, the new science-backed formula put forth is certainly more useful to those looking to calculate dogs’ “human age” than the long-debunked “multiply by 7” myth.


Statistics from pet insurance companies, breed-club surveys, and veterinary hospitals have helped us learn more about how dog’s age.

Contrary to common belief, dogs do not age at a rate of 7 human years for each year in dog years.

According to the American Veterinary Medical Association:

  • The first year of a medium-sized dog’s life is equal to approximately 15 years of a human’s life.
  • The second year of a dog’s life equals about nine years for a human.
  • And after that, every human year equals approximately four or five years for a dog.


(dog’s age in equivalent human years, based on stage of breed size)

Age of Dog Small Medium Large
1 year 15 15 15
2 year 24 24 24
3 year 28 28 28
4 year 32 32 32
5 year 36 36 36
6 year 40 40 40
7 year 44 44 44
8 year 48 48 48
9 year 52 52 52
10 year 56 56 56
11 year 60 60 60

How Do Researchers Come Up With Those Numbers?

There are many several factors to consider, so it’s not possible to pin it down precisely, but the AVMA says: “Cats and small dogs are generally considered ‘senior’ at seven years old, but we all know they’ve got plenty of life left in them at that age. Larger-breed dogs tend to have shorter lifespans compared to smaller breeds and are often considered senior when they are 5 to 6 years of age. The ‘senior’ classification is based on the fact that pets age faster than people, and veterinarians start seeing more age-related problems in these pets. Contrary to popular belief, dogs do not age at a rate of 7 human years for each year in dog years.”

An example would be the Great Dane. The average life expectancy, according to the Great Dane Club of America, is about 7–10 years. Therefore, a 4-year-old Great Dane would already be 35 in human years. Again, keep in mind that these are rough estimates.

The National Center for Health Statistics doesn’t keep records for dogs. Instead, there are three main sources for data on their longevity: pet insurance companies, breed-club surveys, and veterinary hospitals.

How old is my dog?

If you’ve adopted a puppy or dog but don’t know their history, you may not know how old they are. Even if you don’t know the birth date, you can still guess their age.

Their teeth should give you a rough idea of their age. These guidelines will vary from dog to dog, and they also depend on the kind of dental care (if any) they had before you got them.

Age of Dog Human Equivalent Indicator(s)
8 weeks 3-4 years Baby teeth have finished growing
7 months 8-10 years All permanent teeth have grown
1-2 years 15-24 years Teeth starting to yellow and duller
3-5 years 28-36 years Tooth wear and plaque build-up is common
5-10 years 36-66 years Teeth and gums show some signs of disease
10-15 years 56-93 years Teeth well worn, lots of plaque and some may be missing

Your vet can also guess their age based on a complete physical exam or tests that look at bones, joints, muscles, and internal organs. Senior dogs might show some specific signs of aging.

  • Cloudy eyes
  • Gray hair. It starts around the muzzle then spreads to other areas of the face, head, and body.
  • Loose skin
  • Stiff legs

Why Do Smaller Dogs Live Longer than Larger Dogs?

This phenomenon has baffled scientists for years, and research has yet to explain the relationship between body mass and a dog’s lifespan.

Generally speaking, large mammals, like elephants and whales, tend to live longer than small ones, like mice. So why do small dogs have a longer average life span than large breeds?

Large dog’s age at an accelerated pace, and “their lives seem to unwind in fast motion,” according to researcher Cornelia Kraus, an evolutionary biologist at the University of Göttingen in Germany, speaking to Inside Science. Scientists concluded that every 4.4 pounds of body mass reduced a dog’s life expectancy by about a month. The reason why is still unknown, though Kraus puts forward several possibilities, including that larger dogs may succumb to age-related illnesses sooner and that the accelerated growth of large dogs may lead to a higher likelihood of abnormal cell growth and death from cancer. Scientists plan future studies to better explain the link between growth and mortality.

Whether measured in human years or dog years, as our dogs mature and age there is beauty and charm at every step along the way. With their gray muzzles and wise expressions, senior dogs are especially lovable and poignant.

What Can I Do to Increase My Dog’s Life Expectancy?

If you just brought home a new puppy, you are probably not too worried about his life expectancy since the average lifespan of a dog is anywhere from 10–15 years. Some dogs live a lot longer than the average, so as your dog gets older, you will probably want to find out what you can do to keep them healthy.

Are there things you can do to increase his life expectancy? A dog’s life is partially determined by his genetics. His future is not set in stone, but you can make a difference by how you care for him. The sooner you start some of these changes the better, so get started right away.

Keep him at a healthy weight.

It’s so easy to let your dog get overweight. When he looks at your with those sad, soulful eyes, begging for just a “little, teeny, tiny morsel of that delicious steak,” it’s hard to turn him down. But too many treats and/or too much, or the wrong sort, of dog food can pack on the pounds.

Overweight or obese dogs are at higher risk for a whole host of diseases, including high blood pressure, kidney disease, heart disease, diabetes, and even cancer. Feeding your dog the right food for his age, activity level, breed, and any health conditions can go a long way towards keeping him at his best weight and health.

Exercise Your Dog Daily

Your dog needs at least some exercise every day. Most dogs have fenced yards or live indoors most of the time. While this keeps them safe from many dangers, it cuts down on the amount of exercise your dog would get if he were patrolling the world on his own.

The type and amount of exercise your dog needs should be tempered by his age, overall health, and activity level that is natural for his breed, but dogs should get at least 30 minutes of exercise every day. It will help keep him lean, his muscles toned and will stimulate his mind.

Give Him Food Puzzles

Speaking of minds, your dog needs to keep his gray matter active, too. Dogs are intelligent animals and they like to have problems to solve. Toys that have food in them that require some thought or work on the dog’s part to get the food out can help keep your dog young at heart, sharp, and keep him from being bored. And a bored dog is often a destructive dog. Just make sure you take into account the extra calories from those treats when you are determining how much to feed him at dinnertime.

Brush His Teeth Regularly

Your dog’s teeth need to be brushed daily, or at least several times a week. There are all sorts of different doggy toothbrushes you can get. Some treats are good for keeping teeth clean as well. Good oral health helps your dog maintain good overall health.

Take Him to the Vet for Regular Visits

Be sure to take your dog for routine wellness checkups. Most adult dogs only need to see their vets once a year if they’re healthy. Your vet can let you know if your dog should come in more often. In many cases, the sooner a health issue is discovered, the easier it is to cure or at least manage and control.

Give Him Love and Attention

One of the most important things you can give your dog is free: your love. Your pooch’s world rises and sets on your shoulder. There is nothing that gives him greater joy than when you spend a few minutes with him, rubbing his favorite spots and telling him what a good dog he is. Giving your dog daily doses of your undivided attention and letting him know how much you love him will help keep him by your side for the longest possible time.

What Supplements Will Make My Dog Live Longer?

  • Omega fatty acids : Dogs need the polyunsaturated fats in omega-6 and omega-3 fatty acids to reduce inflammation and prevent painful joints when they are young. Fatty acids can also decrease joint pain as they grow old. Since omega-6 fatty acids will be present in so many parts of his diet, it is important to supplement omega-3 acids with sardines and good quality fish oil.

  • Antioxidants: These supplements are important since they destroy free radicals that will cause your dog to age. If your dog is on a homemade diet, any of the raw vegetables we feed our dogs contain high levels of antioxidants. I give my dogs acerola. This amazing fruit provides a high level of vitamin C, one of the most effective antioxidants available. Although dogs are known to produce their own vitamin C, it is not enough to meet the needs of the body.

  • Probiotics: These are the good bacteria that your dog needs to stay young. I allow my dogs to consume all of the fresh horse manure they want to keep healthy, but if this is not possible (or you do not want to deal with the smell) give your dog yogurt, kefir, or one of the commercial probiotics supplements.

  • Glucosamine: This supplement will slow your dogs aging by reducing the inflammation in his joints. When fed a raw food diet that includes chicken feet, beef tracheas, or beef tails, glucosamine is already available to your dog. If you do not feed your dog correctly, you will need to buy the commercial supplements which may or may not have the amount of glucosamine that is advertised on the label.

Will Exercise Make My Dog Live Longer?

Adequate daily exercise will keep your dog thin, which is one of the most important factors in increasing his lifespan. Going for a brisk walk a few times a day will also extend his lifespan. Mental stimulation when out exercising is also important to keep a dog from developing memory loss in his old age. It may even be important to prevent the development of Canine Cognitive Dysfunction (dog dementia).

Longest Living Dog Breeds

One of the best predictors of a long, happy canine life is the quality of care provided to the dog, but there are other factors that come into play, particularly the dog’s breed.

Here is a list of the 10 dog breeds that live the longest, along with their average lifespans. In general, smaller dogs live longer than their larger counterparts, so you’ll notice a number of petite pooches on the list!


Females of this breed tend to live one year longer than their male counterparts, but all Maltese pups are expected to have long lifespans since they suffer from few serious genetic diseases.

Average lifespan: 15 years


The oldest known Beagle was named Butch, who lived in Virginia and died at the ripe old age of 27 in 2009.

Average lifespan: 15 years

Australian Shepherd

Aussies are known for their excellent herding ability, intelligence, and high energy — and they’re also one of the larger dogs on this list.

Average lifespan: 15 years

Shih Tzu

These “lions” were sweethearts of the Chinese Ming Dynasty, and today they live long lives as companion animals throughout the world.

Average lifespan: 15 years

Lhasa Apso

The oldest Lhasa apso on record lived a whopping 29 years and passed away in 1939. They’re known as good indoor watch dogs since they tend to be suspicious of strangers.

Average lifespan: 15 years


This is a hybrid breed — a cross between a Cocker Spaniel and a Poodle — but their lifespan must be inherited from their Poodle side, since Cocker Spaniels generally only live between 10 and 14 years.

Average lifespan: 16 years

Jack Russell Terrier

These pups are well known for their high level of energy. Maybe that’s what keeps them going so long!

Average lifespan: 16 years

Toy Poodle

All poodles and poodle mixes have a fairly long expected lifespan, but as the littlest of the group, toy poodles have the longest.

Average lifespan: 16 years


They may be the smallest dog breed, but they can also boast being one of the longest-living, largely because they are not prone to any serious genetic illnesses.

Average lifespan: 17 years

Dogs live longer when fed the right foods

Treating dogs’ right

According to the American Kennel Club, the following “people” foods are fine as treats for dogs. Remember, the operational word here is treats. These should never be a substitute for a dog’s regular food.

Yes, dogs can eat apples. Apples are an excellent source of vitamins A and C, as well as fiber for your dog. They are low in protein and fat, making them the perfect snack for senior dogs. Just be sure to remove the seeds and core first. Try them frozen for an icy warm weather snack.

Yes, dogs can eat bananas. In moderation, bananas are a great low-calorie treat for dogs. They’re high in potassium, vitamins, biotin, fiber, and copper. They are low in cholesterol and sodium, but bananas should be given as a treat because of their high sugar content, not part of your dog’s main diet.

Yes, dogs can eat blueberries. Blueberries are a superfood rich in antioxidants, which prevent cell damage in humans and canines alike. They’re packed with fiber and phytochemicals as well. Teaching your dog to catch treats in the air? Try blueberries as an alternative to store-bought treats.

Yes, cranberries are safe for dogs to eat. Both cranberries and dried cranberries are safe to feed to dogs in small quantities. Whether your dog will like this tart treat is another question. Either way, moderation is important when feeding cranberries to dogs, as with any treat, as too many cranberries can lead to an upset stomach.

Yes, dogs can eat cucumbers. Cucumbers are especially good for overweight dogs, as they hold little to no carbohydrates, fats, or oils and they can even boost energy levels. They’re loaded with vitamins K, C, and B1, as well as potassium, copper, magnesium, and biotin.

Yes, cantaloupe is safe for dogs. Cantaloupe is packed with nutrients, low in calories, and a great source of water and fiber. It is, however, high in sugar, so should be shared in moderation, especially for dogs who are overweight or have diabetes.

Yes, dogs can eat mangoes. This sweet summer treat is packed with four different vitamins: A, B6, C, and E. They also have potassium and both beta-carotene and alpha-carotene. As with most fruits, just remember to remove the hard pit first, as it contains small amounts of cyanide and can become a choking hazard. Mango is high in sugar, so use it as an occasional treat.

Yes, dogs can eat oranges. Oranges are fine for dogs to eat, according to veterinarians, but they may not be fans of any strong-smelling citrus. Oranges are an excellent source of vitamin C, potassium, and fiber, and in small quantities, the juicy flesh of an orange can be a tasty treat for your dog. Vets do recommend tossing the peel and only offering your dog the flesh of the orange, minus any seeds. Orange peel is rough on their digestive systems, and the oils may make your dog literally turn up their sensitive nose.

Yes, peaches are safe for dogs to eat. Small amounts of cut-up fresh or frozen peaches are a great source of fiber and vitamin A, and can even help fight infections, but just like cherries, the pit contains cyanide. As long as you completely cut around the pit first, fresh peaches can be a great summer treat. Skip canned peaches, as they usually contain high amounts of sugary syrups.

Yes, dogs can eat pears. Pears are a great snack because they’re high in copper, vitamins C and K, and fiber. It’s been suggested that eating the fruit can reduce the risk of having a stroke by 50 percent. Just be sure to cut pears into bite-size chunks and remove the pit and seeds first, as the seeds contain traces of cyanide. Skip canned pears with sugary syrups.

Yes, pineapple is safe for dogs to eat. A few chunks of pineapple is a great sweet treat for dogs, as long as the prickly outside peel and crown are removed first. The tropical fruit is full of vitamins, minerals, and fiber. It also contains bromelain, an enzyme that makes it easier for dogs to absorb proteins.

Yes, dogs can eat raspberries. Raspberries are fine in moderation. They contain antioxidants that are great for dogs. They’re low in sugar and calories, but high in fiber, manganese, and vitamin C. Raspberries are especially good for seniors dogs because they have anti-inflammatory properties, which can help aging joints. However, they do contain small amounts of xylitol, so limit your dog to less than a cup of raspberries at a time.

Yes, dogs can eat strawberries. Strawberries are full of fiber and vitamin C. Along with that, they also contain an enzyme that can help whiten your dog’s teeth as he or she eats them. They contain sugar, so be sure to give them in moderation.

Yes, dogs can eat watermelon. It’s important to remove the rind and seeds first, as they can cause intestinal blockage, but watermelon flesh is otherwise safe for dogs. It’s full of vitamin A, B-6, and C, as well as potassium. Watermelon is 92 percent water, so it’s a great way to help keep your dog hydrated on hot summer days.

Yes, broccoli is safe for dogs to eat in very small quantities and is best served as an occasional treat. It is high in fiber and vitamin C and low in fat. However, Broccoli florets contain isothiocyanates, which can cause mild-to-potentially severe gastric irritation in some dogs. Furthermore, broccoli stalks have been known to obstruct the esophagus.

Brussels sprouts
Yes, dogs can eat Brussels sprouts. Brussels sprouts are loaded with nutrients and antioxidants that are great for humans and dogs, alike. Don’t overfeed them to your dog, however, because they can cause lots of gas. Cabbage is also safe for dogs, but comes with the same gassy warning!

Yes, dogs can eat carrots. Carrots are an excellent low-calorie snack that is high in fiber and beta-carotene, which produces vitamin A. Plus, crunching on this orange veggie is great for your dog’s teeth (and fun).

Yes, celery is safe for dogs to eat. In addition to vitamins A, B, and C, this crunchy green snack contains the nutrients needed to promote a healthy heart and even fight cancer. As if that wasn’t enough, celery is also known to freshen doggy breath.

Green beans
Yes, dogs can eat green beans. Chopped, steamed, raw, or canned – all types of green beans are safe for dogs to eat, as long as they are plain. Green beans are full of important vitamins and minerals and they’re also full of fiber and low in calories. Opt for low-salt or no-salt products if you’re feeding canned green beans to your dog.

Yes, dogs can eat peas. Green peas, snow peas, sugar snap peas, and garden or English peas are all OK for dogs to find in their bowl on occasion. Peas have several vitamins, minerals, and are rich in protein and high in fiber. You can feed your dog fresh or frozen peas, but avoid canned peas with added sodium.

Yes, dogs can eat spinach, but it’s not one of the top vegetables you’ll want to be sharing with your pup. Spinach is high in oxalic acid, which blocks the body’s ability to absorb calcium and can lead to kidney damage. While your dog would probably have to eat a very large amount of spinach to have this problem, it might be best to go with another vegetable.

Frequently Asked Questions

1- Is a Dog Year 7 human years?

Contrary to common belief, dogs do not age at a rate of 7 human years for each year in dog years. The first year of a medium-sized dog’s life is equal to approximately 15 years of a human’s life. The second year of a dog’s life equals about nine years for a human.

2- How many years are in 1 year for a dog?

If you own a dog, you’ve heard this rule: 1 year for Fido equals 7 years for you. Turns out, the math isn’t that simple. Dogs mature more quickly than we do early on. So the first year of your fuzzy friend’s life is equal to about 15 human years.

3- Why do dogs die so fast?

So why do bigger dogs die sooner? According to new research, it’s because they age faster. Large dog’s age at an accelerated pace, as though their adult life is running at a faster pace than small dogs’. Hence, the first answer to the question of why large dogs die young is that they age quickly.

4- How old is a 2 month old dog?

Averaged together for both brain and body development, a two-month-old puppy is probably about the same age as a one-year-old human. At one month, he is probably closer to a six-month-old human. At four months old, he is probably roughly the same age as a two or three-year-old human.

5-What dog can kill a lion?

Ten dog breeds are noted for their ability to catch and kill wild ones: Rottweiler, Wolf dogs, Neopolitan and Tibetan mastiff, Boerboel dogs, Rhodesian Ridgeback, and Bloodhounds, Fila Brasileiro, Dogo Argentino, and Kangals.

6- Do dogs recognize faces?

Dogs do pay attention to human faces, Andics, said. “They read emotions from faces and they can recognize people from the face alone, but other bodily signals seem to be similarly informative to them.“They go through a several months-long training,” Andics said.

7- Why do dogs only live 15 years?

Lifespan in general is determined by trade-offs between survival and reproduction. Wolves, the ancestors of dogs, can live 15-20 years, roughly twice as long as comparable-sized dogs. So the whole life history of dogs is shifted to more of a “live fast, die young” style compared to wolves.

8- Do dogs understand when humans die?

Fox said dogs definitely mourn, that some even realize their owner is dead before the hospital calls the family, though there’s not much evidence to support that. Animal behavior expert Sarah Wilson told People it’s not so much about dogs mourning than them not understanding why you’re not around anymore.

9- Do dogs live longer if they are loved?

Happier dogs tend to live longer lives. Don’t forget to do things with your dog that he absolutely loves. If you brought your dog to the beach one summer and he just about lost his mind he loved it so much, make a point to go more next year.

10- What is the smartest dog in the world?

Border Collie
The smartest dog in the world is a Border Collie called Chaser.


“One dog year equals seven human years” method has been around for years, it’s not very accurate. Luckily, with new research, we now have a more accurate way of estimating the age of our dogs.

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