What Age Do Horses Stop Growing? (Horse Growth Stages and Chart)

It is a confusing question, right? Well, yes, it is, but there is no proven or used method to determine the age at which horses stop growing. It only depends on a few factors that you have to watch closely to guess at what age they would stop growing.

horses growing

So, at what age do horses stop growing? The factors that determine that the horse has fully grown are, skeletal maturity and psychological maturity. Although, the age of the full-grown horse can be guessed by factors like genes, breed and nutrition. Some horses are said to be fully grown until 4-5 years of age and some heavy bred horses aren’t completely grown until they’re 7-8 years old.

Let’s take a look at all of these factors to determine at what age your horse is likely to stop growing:

What age does horse’s skeleton stop growing

The bodily height and weight tell you a lot about the maturity of the horse’s age. Although, different breeds of horses are subjected to grow by taking separate amounts of time. The skeleton of a horse plays crucial part in making him a fully grown horse and until the skeleton system of the horse is not stable, it is unsafe for riding. There are growth plates present under every bone of the horse’s body that fuse gradually when they’re growing up. Of course, there aren’t any present under the skull. These growth plates are of three kinds and they are namely, femurs, hocks and tibias. These plates are made of cartilage, which means that they can be damaged is heavy weight is put on them. The estimated age of the horse should be around 6 years until its skeleton plates have merged to form part of the bone and when the horse is safe for riding. But beware! This is not the case in all horses as skeleton plates in some breeds take even more time to fuse, maybe 7 or 8 years.

What age does a horse’s mental age stop growing?

Not just skeletally but horses also grow mentally and until they reach that mature mental level they’re unsafe to ride or train as they wouldn’t have the understanding and might do things wrong that could damage them physically. Other than that, horses under sufficient brain maturity level will be confused of the commands you give them and they may get frustrated at that and ignore your commands or show anger which can be dangerous for the horse and you as well. The age at which horses reach the full psychological maturity can be from 5 to 7 years old, but pay close attention to your horse and it’s habits to determine if it’s fully grown or not, in fact, give it a little more time until it’s comfortable enough to start getting trained and ridden to avoid any consequences.

Genes determine how tall a horse is going to be

The breed and genes of the horses have an important part in determining that at what age the horse is going to stop growing. Some breeds like the Thoroughbred, have genetics of having larger height than that of the Quarter Horse. If you want to have an idea of how much tall your horse is going to be when it is fully grown, then look up the final weight and height of that breed and it will be somewhat similar to that of your horse. Though horses take the height of their inherited genes of the type of breed, it’s not for sure that they’d reach that height at the given age given in their genes due to some factors that affect the growth process. So, it cannot be determined exactly at what age your horse is going to be when it’s fully grown through genetics unless taking in mind other factors that also take part in determining it. Accidents like bone fracture or malnutrition can slow down the growth of a horse and make him age slower than other kinds of its breeds

Nutrition can affect growth rate

The feeding or forage given to horses during their younger days can give you an idea of the age at which they’d get fully matured. The better the feeding regime of the horse in his younger days, the better his health would be, and he would grow more efficiently according to its genetics. If the horse had been given less or bad feed to the point that it becomes unhealthy, then that would inversely affect the horse’s growth and he might grow later than what his genes say about his height. Not only the quantity but the quality of their feed should be good for giving them good nutrients to grow according to their age. Overfeeding your horse won’t make him grow faster, in fact, overfeeding it can cause serious harm to his body and hence slow down its growing process. Some folks overfeed their horses to make them look bigger for their ages for showing them or riding them, which is a very dangerous and risky thing to do with your horse and you should refrain from it.


I have owned over 50 horses and currently own a small horse farm with 8 horses. I have competed on and off for over 25 years while doing mostly trail riding and cow sorting these days. I write these articles to help anyone out there if you love this article pin it to your Pinterest or Share on other social media platform. Thanks for visiting.

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