The simplest way to measure an archer's ideal draw length is to divide arm span by 2.5 and round down. This is because proper archery form requires the bow arm to be almost fully extended and the string arm brought to the center of the body at full draw.Continue Reading
Have the archer stand straight and hold her arms parallel to the floor. Then, using a locking tape measure, find the length between the tips of the middle fingers.
Divide the arm span by 2.5 for the ideal draw length. An archer with an arm span of 65 inches, therefore, has a draw length of 26 inches. If necessary, round down to the nearest half-inch.
Measure the bow at the draw length indicated by the calculation. The archer should stand in a shooting stance, hold the bow and draw the string to a full draw. She should be barely able to nock the string at the anchor point just below the jawline or behind the ear with little to no further give in the bow. Remember that people have different arm measurements, and the arm span measurement is the closest approximation that applies in most situations.