A farrier's tool and a method of using the tool for preparing the hoof of a horse to receive a shoe. The tool is, in one aspect, a goniometer used for determining the angle of heel-toe taper when preparing a horse's hoof to receive a shoe. After the angle between the anterior surface of the first phalanx of the foot and the anterior surface of the hoof is determined, the ground-facing surface of the hoof is beveled by means of a trimming tool at an angle determined by the goniometer to reduce uneven pressure on the underlying coffin bone and to balance the tension on the tendons and ligaments in the horse's foot, particularly during locomotion. The method provides, inter alia, means for accurately aligning the hoof capsule with the coffin bone in the hoof.