Tips on how to determine a dog’s age — it’s part science and part artful guesswork.
By Karen B. London, PhD
woman determining age of older dog while puppy watches
Thirdman / Pexels
If you’re considering adopting a rescue dog, you’ll likely know little about their history. But as any eager pet parent, you probably can’t help but wonder about their past — whether it be their breed ancestry or their age. Finding out the age of puppies is easy, but with older dogs, is it possible to determine how old they are?

Although the question may seem straightforward, providing a dependable answer is actually quite complicated. There are a number of clues that can be used to estimate a dog’s age, but the accuracy of the guess may be anywhere from close to the truth to wildly off. Why? Like people, each dog visibly ages at a different rate, and a dog’s size, breed makeup, and past health and activity level affect how they age. Here are a few techniques you can use to estimate your dog’s age.

Six ways to tell a dog’s age

1. Teeth

One of the most prominent ways to tell a dog’s age is through teeth. Puppies have baby teeth that fall out and are replaced in a fairly predictable, age-dependent pattern, so very young dogs can typically be aged accurately by examining their teeth. Most dogs will have all of their adult teeth by the time they are about six months old, and once that happens, the teeth offer less exact information about age.

Generally, the condition of the teeth will change with age: they have more tartar, wear and tear, a flattened appearance, and gum disease. Dogs have a complete adult set of teeth between six months old and one year that appear clean and bright white. By fifteen months, the lower incisors begin to show some signs of wear. As dogs age, typically between eighteen months and three years, the cusps on their lower incisors and lower premolars will wear down, while the cusps on their upper incisors may show some signs of wear. Their teeth wear down and flatten over time, and by age four, they may have tartar buildup and yellowing.

However, factors such as diet, chewing habits, and genetics all have such a large influence that it is not unusual to see a young dog with teeth in poor condition or an old dog with relatively healthy teeth.

2. Eyes

Another way to tell a dog’s age is lens clarity. Middle-aged and senior dogs often have a haze on the lenses of their eyes, making the eyes look a little blue or cloudy. This haziness is called lenticular sclerosis and does not change the transparency of the eye to light and doesn’t affect vision like cataracts do. With lenticular sclerosis, dogs do not go blind; they just have difficulty detecting small details.

Lenticular sclerosis is a normal change in dogs’ eyes as they age and usually occurs in both eyes. About half of all dogs will show this condition by the age of nine, and within a few more years, it’s present in almost every dog.

3. Body condition

Puppies under a year old have round bodies and loose skin. Their skin is so big for them that it often seems like a second puppy could fit in there with them. Puppies have all this extra skin so they have room to grow as they age.

On the other end of the spectrum, a dog’s weight distribution changes with age. Older dogs will often have fat pads in their lower back area and a prominent spine. Loss of muscle occurs as dogs get older, too.

4. Body movement

Puppies and young dogs will often trip over their paws as though they were just placed in this new body and are trying to figure out how to operate it. Sometimes puppies seem a bit confused about the proper order of leg movement, and it doesn’t always look like they have it right.

Puppies typically have a sort of bounce in their step when they walk or run. With older dogs, you’ll see a swayback indicating that a dog is more of a senior citizen than a spring chicken.

5. Graying fur

Graying around the muzzle and eyes certainly makes dogs look older, but this isn’t a clear sign of age. Many dogs start getting that distinguished silvery look when they are only a few years old, while some senior dogs still have their original color.

Studies have shown that many young dogs experience premature graying due to anxiety and fear — basically, they get grays when stressed, just like we do.

6. Overall appearance

If you’ve adopted an adult dog, an age estimate may not be super accurate, but as time goes on, you might be able to improve your guess. If you’ve had an adult dog for several years and any changes in general appearance are minimal, your dog was probably pretty young when adopted, perhaps two, three, or four years old at the time.

  • Medium and large dogs from age two to eight can be remarkably similar in appearance, so it’s only as they age out of that range that it’s easier to determine when they were born.
  • Smaller dogs who have not changed in several years have a wider starting age range — perhaps from one to five years at adoption.

Your vet’s age assessment

You can ask your vet to help you figure out how old your dog is. Your vet will utilize many of the methods above to help make a determination.

Besides your dog’s physical appearance, one major clue about age is how long you (or the rescue) have had the dog, so your veterinarian will probably ask you that just to determine a starting point. (If the dog was at the shelter for three years, the dog can’t be only two years old!)

The task of determining a dog’s age can be quite challenging for a veterinarian, as it often requires a significant amount of guesswork. As a result, it is not uncommon for them to provide an unsatisfying age range rather than a specific age. Bummer.

FAQs (People Also Ask):

How can I find out how old my dog is?

The rescue you adopted your dog from will have the best clues on how old your dog is. A veterinarian can also help you determine the age of your dog by looking at their teeth, eyes, and overall appearance.

How can you tell a dog’s age?

You can tell a dog’s age by looking at their teeth, eye clarity, body condition, movement, and overall appearance. Their breed, health, size, and activity level will also play a role in how they age.

Can a vet tell how old a dog is?

Yes, a veterinarian can give a general estimate of how old a dog is. But because a variety of factors impact how dogs age, they likely cannot provide a wholly accurate estimate.

How do you tell the age of a female dog?

You can tell the age of a female dog by looking at the same overall physical appearance as any other dog: their teeth, body condition, and eye clarity.

How do you tell the age of a male dog?

Much like female dogs, you can tell the age of a male dog by making an assessment of a dog’s body condition: how their teeth look, their eye clarity, their spinal curvature, and fatty deposits.

How do you tell how old a rescue puppy is?

Your vet can determine the age of your puppy by reviewing their teeth. Puppies predictably lose their teeth starting around 12 weeks old and typically will have their full set of adult teeth by six months old.

How do you tell a dog’s age by teeth?

A puppy’s adult teeth typically arrive quickly and orderly, helping to give insight into their age. Puppies gain their permanent incisors between two and five months, their canines around five months, their premolars between four and six months, and their molars by seven months.

How do you tell how old a stray dog is?

It’s best to take stray dogs to a local veterinarian or animal shelter where they can check for a microchip and, if needed, determine the dog’s age.


Lenticular Sclerosis in Dogs

Eye Health and Canine Cataracts

Dog Spine Issues

Lumbosacral Disease in Dogs

Anxiety and Impulsivity: Factors Associated with Premature Graying in Young Dogs

Age Determination in Dogs

Inflammatory Pattern of the Infrapatellar Fat Pad in Dogs with Canine Cruciate Ligament Disease


Karen B. London, Ph.D., is a Certified Applied Animal Behaviorist and Certified Professional Dog Trainer who specializes in working with dogs with serious behavioral issues, including aggression, and has also trained other animals including cats, birds, snakes, and insects. She writes the animal column for the Arizona Daily Sun and is an Adjunct Professor in the Department of Biological Sciences at Northern Arizona University. She is the author of six books about training and behavior, including her most recent, Treat Everyone Like a Dog: How a Dog Trainer’s World View Can Improve Your Life.