Horse Growth Guide: When Do Horses Stop Growing?

A common question that new horse owners ask is when will their horse stop growing and reach its full size. Here’s what I’ve been able to learn as the owner of several horses over the years.

When does a horse stop growing? Many horse breeds grow close to their final height by the age of 4 or 5 years old, then fill out more over the next 2 or 3 years. Large horse breeds like draft horses don’t stop growing until they are 8 years old. 

The final size of a horse can be impacted by a variety of factors, like genetics and breed. I once had a quarter horse/Arab cross that grew an entire hand as a four-year-old! If you’re trying to determine what size your horse will end up being, here is more information that will help.

Horse Growth Rate by Breed

Quarter Horses. Quarter horses become fully grown at the age of 4 or 5 years old.

Thoroughbreds. Thoroughbreds also become fully grown at the age of 4 or 5.

Arabian Horses. While most horses reach their full height by 4 or five years old, it’s believed that Arabian horses reach their maximum height around the age of 6 years old. 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.

Draft Horses. Draft horses tend to become fully grown anywhere from 5 to 7 years old.

How to Tell How Tall a Horse Will Grow 

Unfortunately, there is no definitive method to tell you exactly how tall your horse will grow. But there are ways to get an idea, even while they’re young. Chances are, the horse will take after their parents when it comes to height because genetics is a major determining factor.

If you’re able to, you can ask for the measurements from the horse’s parents to get an idea of how tall your horse might be. Another good option is to check with anyone you know that has the same breed of horse to see how tall their horses are.

It’s good to remember that a lot of growth happens within the first year of a horse’s life. By around 12 months old, the horse will have reached roughly 90 percent of their height. After this rapid growth period, the growth rate slows down substantially, typically taking another 4 to 6 years for them to finally reach their maximum height and weight.

If a horse is already very tall at one year old, you can factor in that they will likely grow several more inches over the years.

If you have a foal, a baby horse, and you want to get an idea of how tall they could be, look at their legs. A horse’s leg length will rarely grow much longer than when the horse is a baby, so this can be a way to determine the horse’s height. While most foals look lanky and awkward, if your baby has much longer legs than usual, then it’s probably going to end up being a pretty tall horse.

At What Stage of Growth Do Horses Reach Full Emotional Maturity? 

When horses are young, they have a fun playfulness, and tons of energy to run around. However, at this stage, it is more difficult to train them and rely upon on them to follow specific instructions. Just like baby humans, a baby horse can only focus for so long.

Horses normally reach their emotional maturity between the ages of 5 and 7. However, it’s good to keep in mind that all horses have different personalities, experiences, and dispositions that can contribute to their maturity level.

Certain horses may never seem mature to someone that is looking for a very calm horse. Because of this, it’s important that you choose a horse that will be good for your riding needs in the long term. If you need more information on choosing a horse, you can check out the article I wrote on 10 Expert Tips for Choosing the Right Horse.

When is a Horse Grown Enough to Ride? 

When you get a new horse it can be tempting to start riding them straight away, but an important consideration you must make is whether or not they are grown enough to be ridden without resulting in any negative physical side effects.

While some believe that it is safe to ride a horse as young as two years old, the facts show that horses this young should not be ridden because their skeletal structures are not developed enough. Many thoroughbred racehorses are ridden as young as one or two years old, but they often retire by the age of 6 or 7 because of health problems.

If your goal is to have a horse with a long, happy, and healthy life, my recommendation is to wait until the horse is at least 4 years before riding them. This might seem like a long time, but there is still a lot of groundwork training that you can start with them at around 2 years old while you wait for them to grow stronger. For instructions on some groundwork you can do, visit my article on the 5 Best Groundwork Exercises.

If you have any doubts about when to ride your horse, always check with a veterinarian. They will be able to determine whether or not the horse is developed enough to be ridden and if it would be wise to wait a while longer.

Is it Safe to Try to Speed Up the Growth Rate of Your Horse? 

While it is possible to speed up your horse’s growth rate at an early age by the nutrition that you provide to them (source,) this is can be very damaging to the horse’s overall health in the long run.

This is due to the fact that their joints and bones are not fully developed, and are therefore not prepared to bear the additional weight that they will put on so quickly. It is better to feed your horse with their long-term health in mind.

How Can I Measure My Horses Growth? 

The easiest way to track your horse’s growth rate is to take regular measurements utilizing a tape measure and a bendable tape measure. It’s good to keep in mind that you should take your measurements while the horse is on flat ground to ensure you’re getting accurate results.


To measure your horse’s height, you will want to utilize a classic tape measure. You will put the base of the tape measure on the ground beside the horse, and then stretch it straight upwards until it is even with the height of their withers. It can be helpful to hold something on their withers as well so that you form a 90 degrees angle that will easily show you how many inches tall your horse is.

Horses are typically measured in hands. Once you have your height measurement in inches, you can divide that number by 4 to determine how many inches tall they are.


The most accurate way to measure a horse’s weight is by having them stand on a weighing scale. Unfortunately, it’s rare to find a scale larger enough to measure a horse. 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.

To measure with this tape, you simply wrap the tape around the horse’s girth area and up just behind the withers. The tape should fully encircle the body. When this is done, the tape 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

The best way to tell if your horse is fully grown is to take measurements on a monthly basis. You can also compare your horse to the breed information that we have listed above and ask your friends about their experiences with the growth rate of their horses.

You can also take time to research the average height and weight measurements for your particular horse breed. If your horse is still young and falls short of these measurements, there’s a good chance that they still have some growing left to do.

Something I’ve noticed about horses is that once they’ve reached their maximum height, then their body tone will start to fill out. The past two horses I’ve owned started to really fill out once they were around 5 years old. This can be another indicator of maturity.

Another aspect of your horse’s growth to keep in mind is the condition of their feet. A horse’s hooves help to properly distribute weight, circulate fluids throughout the body, and provide traction. It’s important to have your horse’s feet checked regularly, especially if they’re still growing. To learn more, check out our article Horse’s Feet Trim Frequency: Easy Guide.


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Carmella Abel, Pro Horse Trainer

Hi! I’m Carmella

My husband and I started Equine Helper to share what we’ve learned about owning and caring for horses. I’ve spent my whole life around horses, and I currently own a POA named Tucker. You can learn more here.

Thank you for reading, and happy trails!

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