When do horses stop growing? Like most things with horses, there is no one definitive timetable for when horses stop growing. A variety of factors including age, breed, genetics, and management work together to influence how tall a horse will ultimately be.
When they are foals, horses are only approximately only 10% of their ultimate body weight.
Across breeds, the majority of them will reach approximately 90% of their full adult height by the time they are 2. The remaining 10% of growth takes place over the next 2 or so years.
The easiest way to know when your horse has stopped growing is to be constantly tracking their height, so you can see when they reach a plateau.
Full growth is essential to a horse's long and healthy life. Many experts recommend waiting until a horse is at least 4 years old, if not closer to 6 to begin riding.