When do Horses Stop Growing

When Do Horses Stop Growing?

Last updated on November 26th, 2021 at 08:25 pm


During your horse journey, you will undoubtedly have thoughts about either breeding a horse and foaling yourself or you will want to buy and train a baby horse. I have done both and it is a very exciting journey. You will need to know about the growth patterns of the horse for proper training and health.

When does a horse stop growing? Horse growth patterns depend on breeding, most horse breeds get to their maximum height by the age of 5 years old and reach bone maturity by age 6. Larger horse breeds will take longer to fill out and for their bones to mature, smaller horses typically stop growing sooner.

There is a significant difference between the external appearance of a horse, its size and its maturity with that same horse’s internal maturity and it’s readiness for riding, training and competing. The pattern of growth for a horse is significantly longer than most people think, and a horse can still be maturing internally long after it has stopped growing on the outside.

Horse Breeds and Thier Growth Patterns

  • Quarter Horses. 
    • Quarter horses become fully grown at the age of 5 or 6 years old. Even though most people believe they are mature sooner than this the research shows that their bones are still maturing up until this point
  • Thoroughbreds. 
    • Similar to quarter horses thoroughbreds also become fully grown at the age of 5 or 6. Even though racehorses are fully trained and competing at the age of 2.
  • Arabian Horses. 
    • It is believed that Arabian horses take a little longer to reach full maturity. Arabian horses’ skeletal structures have one fewer vertebrae and one less pair of ribs than other horses. They tend to develop much more slowly than other horses.
  • Warmbloods
    • Within the warmblood category, there are a number of breeds. Each of these breeds will take the full 6 years to reach bone maturity.
  • Draft Horses. 
    • Draft horses take the longest to mature because their bones are the biggest and take time to grow. Some draft horses may still be growing at 8 years old. They will also be growing in muscle and body size up until this point as well.
    • Some people wonder about riding a draft horse…yes you definitely can.

Can I Ride a 2 Years old Horse?

Just because someone is doing something doesn’t mean that it is right. And just because a tradition of running two-year-olds at the races has been practiced for years doesn’t mean that biologically the horse is ready for that.

After the skull, all horses have growth plates on every bone in their body. These growth plates are made of cartilage and allow their bones to grow. When the bones have finished growing the growth plates turn into bone, sometimes called fusing, and this makes the bones more durable and less likely to be injured.

Bones in a horse’s legs typically reach maturity in the 4-5 year range, but bones in the back of a horse take longer even up to 6 years.

So can you ride a 2-year-old horse? Obviously the answer is yes, and most people will “start” their horses even earlier than this in some kind of training program. However, many people now believe that you must wait until the horse is at least 5 before rigorous training and competing is to take place.

I foaled a Friesian sport horse a few years ago and it was an awesome process. When she was a baby I started her with the basics in training like halters and being around people. As she aged, I started every spring with something new. Even though she had a saddle on when she was younger, I didn’t start actually riding her till she was 4.

What are the Risks of Riding too Early?

Although it is rare for damage to the legs, or the growth plates by riding too young it can happen. Precaution is the best practice. Many horses however that are started too young have problems later in life and will require injections in their joints. This is because the cartilage is ruined and crushed.

The bigger issue is that you can definitely do damage to a horse’s back when you start riding them too young. Light work and training a horse’s mind and ground manners is the best thing to do until it is a little older.

At What Age do Quarter Horses Stop Growing?

As mentioned above contrary to popular belief quarter horses bones will still be maturing into their 5th year and 6th year depending on the horse. Here is a link to an article that proves it (link).

How to Tell How Tall a Horse Will Grow 

There really isn’t a proven method to actually determine how tall a horse will get. More often than not a horse will follow in the footsteps of its parents. So when you have a foal look at its characteristics and which does it resemble more its mom or its dad? That will give you some insight into what it will look like and how tall it will get. You can also look at its siblings.

Also, remember that a horse is close to 90% of its total height by 12 months of age. They will grow a lot during their first year…they will also be quite gangly looking. One other sign of height is to look at the legs of the horse. Taller horses generally speaking have longer legs in the first year.

Will a 3-year-old Horse Grow anymore?

As mentioned above, yes, a 3-year-old horse will still continue to grow. In fact, it’s during this time that it will start to put on weight and fill out. You can expect it to still grow some in height as well. If your horse’s genetics are typical of the taller variety (16+ hands) you can expect some of the height to happen in this year, although not as much as in year 1 or 2.

Even though your horse will “look” like a mature horse at 3 it is still maturing internally and not ready for full work yet.

When do Horses Reach Full Emotional Maturity? 

I work and run a boarding facility. I know a lot about emotional maturity in horses, and trust me it’s not all about the age. Owners and training a horse for ground manners and good EQ plays a significant part in a horse’s maturity.

When a horse is a baby it doesn’t have a large attention span and will also be very wary of new things. However, it is really important at this stage to be around the foal as much as possible. It needs to learn that humans are ok and that it doesn’t need to be afraid.

Horses typically reach their emotional maturity between the ages of 5 and 7. It is important to know, however, that each horse is different, and the training that each horse receives is very different as well.

emotional growth

When is a Horse Grown Enough to Ride? 

The answer to this question isn’t one size fits all. It is important to know the breeding and growth pattern of your horse. Riding a horse too early can have negative health consequences for the horse.

As mentioned about some people begin riding their horses at 2 or 3, but time after time it is shown that later in life these horses have complications because of this activity. Many people will “rescue” old racehorses and find that their joints and backs need attention because of this.

The earliest you should begin really riding and training a horse is when it is 4 years old. Even then the work that the horse is asked to do in its training program should still be light and moderate compared to older more mature horses.

I am not a vet and not trying to play one on the internet. So, of course, the best advice I can give you is to have a regular vet that knows the history of your horse and is able to work with you on the plan for its training and health.

If you just bought the horse, or don’t have a history it is even more imperative that you have a vet check done to make sure that your horse is healthy and ready for the type of riding that you are going to do. Do not assume that because of the way a horse looks on the outside that everything is ok on the inside. Especially when it comes to bone structure and ligaments.

How Can I Measure My Horses Growth? 

The best way to keep track of your horse’s growth is to measure it. There are measuring tapes you can use and also specific horse measuring tools you can use to measure your horse.

A Horses Height 

To measure your horse’s height, you will want to utilize a classic tape measure. You will put the tape measure on the ground beside the horse and then take it straight upwards until it is even with the height of their withers. It can be helpful to have a ruler or stick on their withers so you can see at a 90-degree angle that will show you how many inches tall your horse is.

Horses are measured in hands. You take the height measurement in inches and divide by 4 to determine how many hands tall they are. Every 4 inches is a new hand. So 13-1 13-2 13-3 13-4 then 14-1 14-2 and so on.


The most accurate way to measure a horse’s weight is to have them stand on a horse scale. Most of the time, however, they are only at the vets.

Another way to do it is to drive your truck and trailer over to the weigh scale and get the weight. Then put your horse in and weigh it again.

There are other methods you can use to get a rough estimate of your horse’s weight, primarily by the use of weight measuring tapes. They are made specifically for measuring horses’ weight.

To measure with a tape, you wrap the tape around the horse’s girth and up just behind the withers. The tape should go all the way around the body. These tapes will give you a general number close to your horse’s weight.

How to Tell When a Horse Has Stopped Growing and Has Reached Their Full Size?

If you take regular measurements and know some of the information about your horse’s breed and genetics that will give you a pretty good understanding of the growth of your horse. You can also consult a vet and other people that have similar horses to determine if you have a fully grown horse.

A horse’s height is one thing when it comes to the growth and maturity of horses. The weight and muscle tone and bone density is another. Those things take longer and usually happen during years 3-6. That’s why it is so important to wait.

Do Older Horses get Arthritis?

Yes, older horses can get arthritis. Obviously, not every old or senior horse gets arthritis, but many do. There are supplements that you can give to your horse to help, there is also Previcox and Equioxx that you can get from your vet.