Ageing A Horse By Its Teeth

Have you ever purchased a horse with no “paper” or gotten a horse from a rescue?  Sometimes sellers are unsure of how old their horses are when their horses don’t have papers or are up for adoption or rescue. Aging a horse by teeth will help you determine its lifespan.

But, knowing how old a horse is can be extremely important for a horse owner to best cater to the horse’s needs and wellbeing.  So, how can a horse’s age be determined without a record or a paper trail?

Ask your equine dentist or vet! They can actually get a pretty good estimate of a horse’s age by the condition of a horse’s teeth.  They typically can’t give an exact birthday or even birth year, but they can give a good estimate that will help a new owner plan for the horse’s wellbeing. 

Common Indicators of Aging a Horse by Teeth

There are several things that a vet or equine dentist will look for in a horse’s set of teeth to determine the horse’s age.  To determine a horse’s age, your vet or dentist will look at the horse’s front twelve teeth, called their incisors. 

The University of Missouri describes the anatomy of the horse’s teeth in the following words: “The two central pairs both above and below are called centers, pincers, or nippers. The four teeth adjacent to these two pairs are called intermediates, and the outer four teeth are designated as corners. Canine teeth or “tusks” may appear midway between the incisors and molars at 4 or 5 years of age in the case of geldings or stallions, but seldom appear in mares. Adult horses have 24 molar teeth.”

In these teeth, your vet or dentist will look for a few characteristics to help determine the horse’s age.  They will look at the shape of the teeth, how many (permanent) teeth a horse has, whether or not “cups” are visible in the horse’s teeth and the angles of a horse’s teeth.

Aging a Horse by Teeth: Shape of the Teeth

The concept here is that the shape of a horse’s teeth will change throughout wear and tear over the years of his life.  When a horse is younger, his teeth are typically broad and flat, resembling something like a rectangle.  But, as he ages, they become more ovular and even triangular.

Permanent Teeth

Typically, by the time a horse is five years old, he will have all of his permanent teeth.  So, if he doesn’t have all of his permanent teeth, he must be somewhere between one and five.  Different teeth standardly appear between a horse’s first, second, third, fourth, and fifth birthdays, so it is relatively easy for vets and dentists to track a horse’s age when they are still this young.

Aging a Horse by Teeth: Cups in Teeth

When a horse has first developed his permanent teeth, there will be a “cup” on their surface, almost like a bowl shape.   Cups fade on certain teeth faster than others, throughout different periods of a horse’s life. The disappearance of this cup shape on certain teeth can give vets and dentists indication of a horse’s age.

Angles of Teeth

Without going into too much vet jargon, the angle of where a horse’s top row of teeth meets its bottom row of teeth can be used to help determine a horse’s age. As a horse gets older, his teeth start to point more outward than inward.  

Aging a Horse by Teeth: Cups in Teeth

Aging a Horse by Teeth: Age Accuracy

But, even with all of these methods, a horse’s teeth can not tell us exactly how old they are.  There are several age groups in particular that are hard to peg.

The first of these is young horses.  Horses under the age of five are constantly growing and so are their teeth.  A young horse’s teeth can change immensely within a 2-3 month time period. Because of this, vets and dentists have to be extra cautious when trying to age young horses.

Conversely, the teeth of horses over the age of 15 don’t really change too much.  At that point, the shape and angles of a horse’s teeth pretty much stay the same unless something drastic happens.

Four Groups Method

In order to combat this unavoidable ambiguity, the AAEP (American Association of Equine Practitioners) created a four-group ageing method.  Basically, they categorize horses into one of four age groups based on the analysis of their teeth.

Their age groups are 1-4 years, 5-9 years, 10-14 years, and 15-20 years.  They concede that ageing a horse over 20 years will pretty much be guess-work. 

In the 1-4 year age group, the AAEP says that they can give a fairly accurate age estimation, so long as they do it correctly. Here, they are looking for whether or not a horse has all of his permanent teeth or not, and how much these teeth have grown in.

In the 5-9 year age group, they are primarily looking at the cups on a horse’s permanent teeth, and to what extent they are still visible.  The shape can also start to be used to help determine a horse’s age during this timespan.

In the 10-14 year age group, tooth shape is the primary indicator of age.  Here, a horse’s teeth will still be square but might be starting to shift toward the ovular shape.  The angle of a horse’s teeth also begins to be relevant during this age group.

And, in the 15-20 year age group, shape and angle are the primary indicators.  The shape will be significantly more ovular than rectangular at this point, and the angle will be noticeably changing.


While ageing a horse by its teeth isn’t an exact science, it can help horse owners have a better idea of how old their horses are.  There are many different factors vets and dentists have to consider when they are ageing a horse by its teeth, and these factors change in importance and relevance over the lifespan of a horse.

I hope this article helped you better understand how vets and dentists age horses by their teeth! If so, please share this article and share with us your experiences ageing horses!

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