🏹 Draw Length Calculator
Measure your wingspan (fingertip to fingertip with arms fully extended) and enter it below to estimate your draw length using the standard formula: wingspan ÷ 2.5.
The wingspan rule
One division, using the long-standing rule of thumb:
draw length (in) = wingspan (in) ÷ 2.5The 70 in default returns 28.0 in; a 74 in wingspan gives 29.6 in. Because the divisor is 2.5, each inch of wingspan is worth 0.4 in of draw, so measuring your span two inches long inflates the estimate by 0.8 in.
Measuring, and what the number is not
- Stand relaxed against a wall. Arms out level, palms forward, shoulders neutral. Stretching for extra reach is the single commonest way this estimate comes out too long.
- It is an estimate, not the ATA measurement. A bow's draw length is taken at full draw from the nock groove to the pivot point of the grip, plus 1.75 in. A draw-check arrow at a shop reads that directly.
- Form moves the real figure. Anchor point, head position, release aid versus fingers and how square you stand can each shift true draw length by half an inch, and the rule knows none of them.
Frequently asked questions
What is my draw length if my wingspan is 70 inches?
28.0 in by this rule. Treat that as the middle of a range roughly half an inch either side, then let a draw check and your own anchor settle it.
How is draw length measured on a bow?
The ATA method measures from the throat of the nock groove at full draw to the pivot point of the grip, then adds 1.75 in. A marked draw-check arrow reads it directly, and it is the number a compound's module is set to.
What happens if my draw length is too long?
The bow arm locks out, the anchor slides back past the face and the string runs close to your nose and forearm, which is where string slap comes from. It also makes a consistent release almost impossible. Too short costs you power and pulls the anchor off the face, but too long is the one that hurts.