How to Tell How Old a Dog Is

Happy pup
Beautiful life

Table of Contents

How to tell how old a dog is? Why would anyone need to know that?! Dog owners need to know the dog’s age in order to assess its general well-being. If the dog is of certain age, but displays behavior and performance uncommon for this age, it certainly means that there is something wrong. Also knowing the life expectancy and the dog’s exact age may prepare the dog owner for the inevitable. This is why it is important to know dog’s age. After all, it is not just a nameless pooch – it is a fellow soul which is as important in your life as any other fellow human.

General Guidelines on Working Out a Dog’s Age

Family dog
Family photo

Dog’s age is not something certain to be easily worked out. It has many variables. In this passage, we will tell you what you should be looking for to get the indication of the actual age of the dog within a couple of years. Assessing dog’s age may be hard to do as dogs from rescue centers do not show the age that the center assessed. Also, mixed breeds bear no evident signs of the dog’s age as they comprise two different breeds with sometimes opposite features. However, the majority of dogs have indicators that do not need much experience to be told. Such indicators depend on genetics, diet, lifestyle and whether it was spayed/neutered or not.


Teeth are the most widely used way of telling the age of dog.

Later in the article, we will dedicate a separate passage to teeth and explain how the calculations are done. Right now, we offer a short sneak-peak into the topic.

Dogs are born with tiny milk teeth that are later replaced with adult teeth. This mechanism works the same way as in humans. The appearance of the teeth, the presence of tartar, the size of incisors and other factors are assessed to tell the almost exact age of the dog.


A dog fed on soft food is more likely to build up tartar and thus, it is sometimes hard to tell the exact age. If the dog’s teeth are regularly brushed, some tartar will be present. It may be prevented by offering the dog more rigid types of food along soft usual kibble. Once again, this may provide false reading of the age (read more Best puppy food).

Giving raw food and meaty bones makes dogs to gnaw on them and thus, they keep own teeth healthy. A dog constantly chewing on bone or a firm toy is free of the normal plaque and tartar growth as well as any gum infections. However, bones are not the target food that should be fed at all times. It’s rather a dental hygiene combined with a treat.

Fear of growingCoat

Human’s skin can tell a lot about our age. No matter how we hide it, what creams we use and how many plastic surgeries and Botox injections we may undergo, the skin will eventually tell everything about us. The same is applicable to dog’s skin and coat. Greying around the muzzle and the top of the head is an evident sign to look for. Nevertheless, some breeds grey earlier – in the middle age, some of them change normal reddish or yellowish patterns into solid white.

As for the skin, it loses elasticity just like in humans due to reduced collagen production and decrease in hydration. If the dog was not regularly exercised, the coat condition will be drier and coarser which tells old age.

Old doggie
This was the great life


Lenticular sclerosis affects many dogs. This condition develops at the age of 6-8 years and is often mistaken for cataracts which is not as common as the sclerosis.

If you spot thin lines across the eye lens, it is a sign that the dog’s pupil will turn slightly grey. It doesn’t affect dog’s vision until the dog is very old. Make sure the dog doesn’t develop cataracts which can be surgically treated.

General Well-being and Performance

If the dog is becoming more sleepless and sluggish, it signifies that it’s getting older or ill. If the transition from normal level of activity to sleeplessness was sudden, it is the sign of illness. Arthritis, weight gain, and bad odor that aren’t going away even after bathing are among the old age indicators.

With the years passing by, the dog’s hearing deteriorates as well while other senses remain relatively normal. However, such signs may not tell the exact age.

Dog’s Age in Human Terms

The myth of dog’s years in correspondence with human’s has practically nothing to do with today’s topic. However, we decided to add this fact to bust the myth and bring more life science than speculations and hearsays. The 1 to 7 year’s calculation is completely incorrect and has no resemblance to how dogs actually age. First of all, comparing two different mammals in terms of lifespan is incorrect. For example, a salamander lives up to 80 years – the same is the blue whale. The first one weighs roughly 20 pounds, while the latter weighs like two M-1 Abrams tanks (above 100 tons). So, what’s the pattern? There isn’t any. As for the dog-human age comparison – maybe, people based their primitive theory on the average lifespan of both. A dog lives 10 years in average, while a human lives 70 years – 1 to 7, right?

Dogs-ageBased on the dog’s behavior, the pace at which they mature and acquire more balanced adult-like temper, dog experts have more exact digits to tell:

  • 1st year of dog’s life can be compared to a child living up to be a 15-16-year old teenager.
  • 2nd year can be compared to our teenager reaching 25 years of age – plus ten years.
  • 3rd year is the time when our subjects reach adulthood: a dog is completely grown up and out teenager is above 30 years of age.
  • Every year after that can be evaluated as +4 years of human life.

If a dog is 12 years old, many would think that it is 84 years old, while the realistic digit tells that it is barely 66 years old – a dog that has just retired and has happy years ahead.

Points to Take into Consideration

Female dogs live 1-2 years longer than males. Small dogs live almost twice the age of the bigger breeds. Also, neutered/spayed dogs live a bit longer when de-sexed after reaching adulthood, but not before that.

Dog’s Teeth as the Best Way of Telling the Age

By examining dog’s teeth you may give a very rough estimate of the dog’s age. The age in puppies is assessed with more accuracy and we’ll pay attention to puppy’s case later.

The Teeth Structure

All dogs have four types of teeth – incisors, canines, premolars and molars. Incisors are small teeth running along the front. Adult dogs have six incisors on the top and six on the lower jaw. Two incisors next to the canine teeth are bigger than the middle ones. Canine teeth are behind the incisors – one on each side, totaling four. These teeth are large and pointed. Premolars are behind canines: there are four of them on lower and upper jaws. Behind the premolars, there are molars – two on the top and three on the bottom jaw.

How the Teeth Grows?

Cute fairytale
Tell me about your youth!

Puppies have 28 teeth normally. First 2-4 weeks of their lives, they have no noticeable teeth. Canines come in after 3-4 weeks, incisors and premolars – after 4-6 weeks. All baby teeth cease growing by 8 weeks. After 5 months, milk teeth will begin falling out and thus permanent teeth will start coming in. First come molars and canines. By 7 months, all permanent teeth are usually completely grown. If a puppy has grown all permanent teeth, then it is likely to be 7 months old at least. Adult dogs have 42 teeth or so.

The tooth wears marks the dog’s age once it surpasses the puppy’s stage. At 1 year of age, teeth are clean and white, but by the end of the year 2 of dog’s life, teeth will show some tartar and the initial whiteness will be a bit dulled. On the rear, the teeth show yellowing which will increase and become visible on all teeth. This is a noticeable tooth wear.

How the Teeth Wears Down?

Tooth wears at own natural pace which is usually accelerated by habits like constant chewing on something hard or due to lack of proper dental care. However, some chewing is good for teeth. For this reason, you should use dental chews or rawhides that break down the plaque. Also by the age of 3 years, 8 dogs out of 10 show signs of gum diseases: the buildup of brown and yellow tartar, inflammation and bad breath. Small dogs are more prone to gum diseases than bigger dogs.

Food plays not the last role in dental health. Dry food helps to remove some plaque and thus slows the tooth loss. Sticking to one type of food just for the safety of teeth is wrong: diet must be balanced and take into consideration all aspects of dog’s health. This is why you should consult your vet about proper diet and products that you should offer your dog. Regular teeth wear poses little health risk, but excessive wear damages roots which may require the root canal dental operation (more about

Dog generation
Remember it, son

Evaluating Condition of Adult Dog’s Teeth

By the age of three years, most dogs exhibit signs of tooth wear and diseases. Teeth accumulate tartar, gums become reddened and you smell bad breath. Those owners who perform dental care at least twice a week will not have these signs (see also’s-Teeth).

The yellowing and tartar buildup increases when the dog is between 3-5 years of age. Gums may leave roots exposed which usually lead to tooth loss. Teeth stained teeth turns from yellow to brown.

From 5 to 10 years, teeth show more increased wear. In the next five years, some teeth may be missing.

How to tell how old a dog is

How to Tell Puppy’s Exact Age

Telling an already developed dog’s age is one thing, but telling puppy’s age is another. Sometimes, one needs to be an expert to tell an approximate age. Why is it important? When you bring your puppy to veterinarian, the first question will be about its age. Moreover, knowing its age is critical when speaking about vaccinations (see also Puppy vaccination).

Puppies are born without teeth with only gums visible. After the 30th day of their life, pupies begin developing their temporary teeth. The process known as the “erupting” results in a total of 28 teeth by the 45th day of age. At this time, puppies are usually given chew toys. At the age of 6-7 months, all teeth are replaced by permanent adult teeth.

Young pup
Too cute

The teeth eruption has own pattern:

  • Incisors: central– 2-5 months, intermediate – 2-5 months, corners – 4-5 months.
  • Canines – 5 months.
  • Premolars: first – 4-5 – months, second – 6 months, third – 6 months, fourth – 4-5 months.
  • Molars: first – 5-6 months, second – 6-7 months, third – 6-7 months.

Using a special formula, vets calculate the puppy’s age by the number of permanent teeth versus baby teeth. Here is how the formula works:

  • Puppies have a total of 28 baby teeth.
  • The formula for baby teeth is 2 (I 3/3 C1/1 PM 3/3) = 28 teeth, where “I” stands for incisor, “C” – for canine and “PM” – for premolars.
  • The formula lists the number of each type of tooth and its placement on the lower/top jaw.
  • The formula lists teeth only on ½ of the mouth – right and left sides are the same. This is why there are “2” before the formula.
  • The formula for permanent teeth is 2(I 3/3 C1/1 PM 4/4 M2/3) = 42 teeth. The letters stand for the same teeth, plus “M” for molars.

If a puppy shows its first molar, its age can be estimated to be 5 months.

Dog Years: Behind the Statistics

More or Less: Behind the stats

If you think that the lifespan depends on the body size of an animal, generally, such statement is true. Elephants and whales live longer than mice and birds. This may lead you to thinking that a Chihuahua has a shorter lifespan than that of a Rottweiler.

Daniel Promislow, professor of genetics at the University of Georgia presents own theory on the matter. The disease that correlates most with the size is the cancer. The rate of cancer increases with age. Increased risk of cancer may be the reason why large dog breeds have shorter lives than small dogs. The latter have a 10% chance of dying because of cancer vs 50% of large dogs. This truth is more baffling especially if you remember that, small dogs reach adulthood faster than big ones.

Sleepy old dog

Promislow also presented his own chart of dog-human age correlation:

First 2 years:

  • 5 years per human year for the first 2 years of small dogs
  • 5 years per human year for the first 2 years of medium-sized dogs
  • 9 years per human year for the first 2 years of large dogs

For 3+ years:

  • For small dogs, there are exact digits: Dachshund (Miniature) 4.32, Border Terrier 4.47, Lhasa Apso 4.49, Shih Tzu 4.78, Whippet Medium 5.30, Chihuahua 4.87, West Highland White Terrier 4.96, Beagle 5.20, Miniature Schnauzer 5.46, Spaniel (Cocker) 5.55, Cavalier King Charles 5.77, Pug 5.95, French Bulldog 7.65.
  • For medium dogs: Spaniel 5.46, Retriever (Labrador) 5.74, Golden Retriever 5.74, Staffordshire Bull Terrier 5.33, Bulldog 13.42.
  • For large dogs: German Shepherd 7.84, Boxer 8.90.

Such baffling but yet truthful age mystery is applicable to dogs only, while other animals show the size-age correlation in general.


How to tell how old a dog is? Check its teeth and watch from aside: how it feels, how it behaves and whether it is sluggish or more active. Dog’s age is something that is hard to tell exactly. Nevertheless, you may tell an old dog from a young sometimes by looking at the grey head and seeing a bit dim glance, you can tell for sure that this old dog is not going to learn new tricks.