How to estimate the age of a dog with an unknown history

How to estimate the age of a dog with an unknown history

In most cases, dogs with a known history will also have a known birthday, or at least, you will be able to find out how old they are to the nearest year by talking to their prior owners or checking out the veterinary history and documentation that comes with them. However, if this is not possible, your detective work may become a little more difficult!

If you find yourself in the position of owning or looking to adopt an older dog, knowing how old they are is a fairly important factor in terms of understanding how to care for them correctly, how to predict their potential lifespan, and how to build up a picture of their prior life experiences and level of understanding.

With some animals such as horses, an experienced person can judge the approximate age of the animal by examining their teeth, and while checking out the teeth can give you some insight into the potential age of your dog, this can be a little hit and miss. However, there are various different clues that you can examine in order to try to determine the approximate age of a dog with some accuracy, and in this article, we will look at these things in more detail. Read on to learn more about how to estimate the age of a dog with an unknown history.

Microchipping information

One of the first things that should be checked on a dog with an unknown history is whether or not they have previously been microchipped by one of their past owners. Even if the information for the prior owner/s is out of date or incorrect, one of the pieces of information that is held by microchipping companies is the age of the dog when they were chipped, and the company itself should be able to give you this information.

Check the teeth

The younger a dog is, the more accurately you can estimate their age by checking their teeth, and this should be the next thing that you look at if microchipping information is not present.

Puppies under one year of age go through a fairly set routine in terms of their tooth development, growth and loss, and so it is not usually hard to tell the age of a dog under one year old. If any puppy teeth are still present, the dog is almost certainly under six months of age, and between six months and one year, all of the adult teeth will usually be present, but the dog’s physical appearance and possibly size will very much indicate a very young dog. If the dog is fully grown and has all of their adult teeth and they are incredibly clean and white, they are probably aged between one and two years old, and at around the age of two, the teeth begin to develop a progressively more yellowish tint to them.

Once dogs are two or older, aging can be estimated by means of the wear and condition of the teeth, the presence of tartar or plaque, and any missing teeth. Your vet is the best qualified person to be able to judge your dog’s age by means of their dentition accurately, so ask them to have a look for you.

Greying fur

As they age, most dogs will begin to develop the odd grey hair or patches of fur, particularly around the muzzle area. Dogs may begin to sport the odd individual grey hair around five years old, but significant greying is unlikely to appear until the dog reaches maturity at around the age of seven.

The eyes

The condition and clarity of the eyes can be helpful in assessing the age of older dogs, and young dogs tend to have very bright, clear eyes that simply glow with youth! Senior dogs may begin to develop clouding in the eyes, or other signs of aging such as a bluish shade, cataracts, or generally, duller eyes than their younger counterparts may have.

Activity levels

In order to assess age by means of your dog’s activity levels, you must also take into account other factors, such as their breeding, diet and general health. A mature border collie is likely to be just as energetic, if not more so, than a young bulldog, and so you must compare like for like within the breed!

Once you have developed a picture of the normal energy levels at different ages for the breed of your dog, how active and willing to play they are can help you to ascertain their approximate age.

The complete picture

Other than if your dog’s microchip gives you a definitive answer, you will need to take all of the different aging factors outlined above into account together in order to try to suss out the correct age of your dog. Once you look at the signs indicated by all of these factors combined, you should be able to make a fairly accurate guesstimate of your dog’s approximate age.



Pets for studWanted pets

Accessories & services

Knowledge hub


Support & safety portal
Pets for saleAll Pets for sale