How much weight can a horse comfortably carry?
To keep our schooling horses going soundly as long as possible, we try to match our riders' height, weight, fitness level and skill with appropriately sized schooling horses. We limit our riders to 220 lbs., unless someone is especially skilled and fit, and a particular horse can safely handle more.
How much weight a particular horse can carry varies, depending on the rider (and tack). The first thing to consider is that it is much easier for a horse to carry a fit, balanced rider who is skilled at sitting over the center of the horse and not bouncing or leaning unevenly. A bouncing, imbalanced rider throws the horse off and makes his work harder. (Try to imagine jogging with a 30 lb. unbalanced pack on your back). A heavier, but experienced rider might be able to ride a smaller horse than a lighter, beginner rider.
To get to a range, some sources list a percentage of the horse’s weight. A common formula says a horse can carry 20% of its own body weight. So, a 1000 lb. horse could safely carry 200 lbs. (including the saddle). In considering this formula, one would want to use the horse's ideal weight -- if a 1200 horse was 200 pounds overweight, it could carry 200 lbs., not 240.
Another formula we feel is important in determining weight carrying capacity is the amount of bone the animal has. “Bone” is determined by measuring the circumference of a horse’s front cannon below the knee. On average, a 1200 lb. horse has 8.5 inches of bone at the cannon. If a horse has more or less bone, they will be able to carry more or less than 20% of their body weight.
A horses's overall condition, age, training, nutrition, height, length and strength of the back, hoof size, and breed are all factors in considering the maximum weight a horse can safely carry without becoming lame or sore in the back.
Click here to see an analysis of a horse's body size to hoof size ratio -- another measurement for determining soundness.