Question:

Is there a way to calculate if the weight of the rider is not too much for the horse?

Answer:

The general “rule of thumb” is a horse can comfortably carry 25% of his own weight. So, for a 1200# horse that means 300# maximum weight on his back. For the average 1000# horse figure  1000 X 25% = 250 pounds.

The can vary, however, depending on the type of horse (light, draft, pony) and the body conformation. A stocky, more muscled breed (think of the Stock QH) can carry a bit more weight than the more delicate Saddlebred, for instance. Of course the general well-being of the horse needs to be considered, as well as the age of the horse. A older horse may not be able to carry a heavy rider or a horse with existing hoof or joint (think arthritis) issues may only be able to carry light riders even though his body weight calculates differently. A horse with past injuries that may interfere with his regular way of going or overall well-being may, again, only be able to carry light riders.

Always be considerate of the individual horse.