They are generally 34 to 38 inches tall at the shoulder when fully grown.
There are two types of miniature horses:
* American Miniature Horses: These horses are generally 34 inches tall or under.
* American Shetland Ponies: These ponies can be up to 46 inches tall, but are often smaller than that.
It's important to note that these are just general guidelines, and individual miniature horses can vary in size.