What Age Do Horses Stop Growing?

It’s crucial for all horsemen to comprehend the concept of a horse’s growth because it’s a hot topic in the Sporthorse industry. Thus, at what point does a horse stop growing? Growth in horses dictates when they can start working and when specific demands can be made of them.

For each category of growth, horses reach their full size at a different period. The three components of their growth are height, weight, and bone. Horses reach their full height before they reach their full length, and they reach their full length before their bone development is complete.

To identify when a horse has reached its maximum development potential overall and in each of these three growth categories, I will cover all three in this post.

When Do a Horse’s Bones Stop Growing?

The growth of a horse’s bones and joints is the most contentious topic in horse growth. Many trainers and owners have strong opinions regarding the optimum age to begin breaking, riding, or jumping a horse. This is due in great part to the expansion of a horse’s bones and joints.

Beginning to work a horse while its bones are still forming has been proven in tests to have unfavorable implications for the horse later in its career. The racing industry, where horses as young as two years old are raced, has been hit the worst by these results. Many European breeders (and even some American breeders) are also jumping horses as young as three years old and advancing up the heights swiftly.

Everyone must make their own decisions about what is best for their horse and training. However, in order to make these decisions, one must first understand the growing process of a horse’s bones and joints.

Plates for Growth

Every bone in a horse’s body, except for the skull, has a growth plate. It can take up to six years for these growth plates to fuse together. This doesn’t mean that horses shouldn’t be broken or ridden until they’re six; it just means that until they’re six, it’s important to remember that they’re still growing and changing.

Make sure that you and your vet have a plan for how to take care of your horse in the best way possible. Your vet should check on your young horse often to make sure it is growing and developing the right way.

Veterinarians can also figure out if a horse is old enough to do certain jobs or tasks based on its growth. Every horse is different, so every rider and trainer will make different choices.

Bone Minerals

Similar to growth plates, horses don’t reach their mature bone mineral content (BMC) until they are six years old. Even slower than a horse’s growth in height and weight is the growth of BMC.

Bone mineral content (BMC) sounds like a scientific term, but it just means that a horse’s bones aren’t fully healthy and strong until they reach their mature BMC level at age six. Like growth plates, this doesn’t mean that horses shouldn’t be ridden until they’re six; it just means that they should be treated with care until all of their body parts have fully grown.

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How tall does a horse stop getting?

The least amount of time is needed for a horse to grow taller. When you think of foals or yearlings, you might picture them as “all legs” and thin. This is because their height has grown faster than their weight.
By the time they are six months old, light riding horses have grown to about 84% of their full height. By the time they are one year old, they are 94 percent of their full-body height. And by the time they are 24 months/two years old, they are 97 percent of their full height.

Equines use a thoroughbred, whose full height is about 15.2 or 15.3 hands, as an example. This horse would be 13.2 hands tall at six months, 15 hands tall at twelve months/one year, and 15.2 hands tall at twenty-two months/approximately two years.
Horses also get longer in about the same amount of time as they get taller. As they grow taller, their spines get longer.

When does a horse’s weight stop growing?

A horse’s length will change more slowly than its height. People who ride horses often say that their horses are “filling out” while they are still young and for a long time. Young horses are often underweight until they have had time to fill out and gain the muscle and fat they need to be healthy, full-grown horses.

At six months, a horse will weigh between 46 and 50 percent of its full body weight, about 65 percent at twelve months/one year, and 90 percent at twenty-two months/about two years. The last 10% will fill in gradually over the next two to three years, depending on the horse and its training program.
Going back to the example from Equinews, this means that a Thoroughbred with a mature weight of 1100 lbs would weigh 506 lbs at six months, 715 lbs at twelve months/one year, and 990 lbs at twenty-two months/approximately two years.

When does a horse’s mind stop getting smarter?

Not only do horses’ bodies change, but their minds do too. Until their minds are fully developed, it’s dangerous to ride or train them because they don’t have enough knowledge and might do things that hurt their bodies. Aside from that, horses whose brains aren’t fully developed won’t understand the commands you give them. This could make them angry, which can be dangerous for the horse and for you as well. Horses reach full psychological maturity between the ages of 5 and 7, but you should pay close attention to your horse and its habits to see if it’s ready. If you’re not sure, give it a little more time until it’s ready to be trained and ridden to avoid any problems.

The genes of a horse decide how tall it will be.

The breed and genes of the horse are important factors in figuring out when the horse will stop growing. Some breeds, like the Thoroughbred, are more likely to be taller than the Quarter Horse because of their genes. If you want to know how tall your horse will be when it’s fully grown, you can look up the breed’s final weight and height. Your horse’s final height and weight will be similar to that of the breed. Even though horses inherit the height of their breed in their genes, that doesn’t mean they’ll reach that height at the age written in their genes. There are a number of things that can slow or speed up the growth process. So, genetics alone can’t tell you exactly how old your horse will be when it’s fully grown. You have to take into account other factors as well. Accidents like breaking a bone or not getting enough food can slow a horse’s growth and make him age slower than other horses of the same breed.

What you eat can affect how fast you grow.

You can get an idea of when a horse will be fully grown by how they were fed or cared for when they were young. If the horse was fed well when he was young, his health would be better and he would grow according to his genes more quickly. If the horse was fed less or bad food to the point where it got sick, it would have the opposite effect on his growth, and he might grow later than his genes say he should. Both the amount and the quality of their food should be good so that it gives them the nutrients they need to grow. If you feed your horse too much, he won’t grow faster. In fact, too much food can hurt his body, which will slow down his growth. Some people overfeed their horses to make them look bigger than they are for showing or riding them. This is a very dangerous and risky thing to do with your horse, and you should not do it.


It can be hard to figure out when a horse stops growing. There are many parts to a horse’s growth, but by the age of six, a horse should be fully grown and developed. Every horse is different, and some can physically do more at a younger age than others.

I hope this article has helped you learn more about how horses grow and when they stop. If so, please share this article and tell us about how you’ve seen young horses grow and change.