How this calculator works
The wingspan divided by 2.5 method is an archery fitting rule of thumb. Stand with arms out horizontally and measure between middle fingertips. Equipment, anchor point, release aid and shooting form can change the correct setting. Have a qualified archery shop verify fit before adjusting a bow. The result is an estimate for information only and is not medical advice.
Formula
Estimated draw length = wingspan/2.5. Wingspan = estimated draw length x 2.5. Both lengths use the same unit.
Worked example
A 70-inch wingspan gives a 28-inch starting draw length. A 75-inch wingspan gives 30 inches.
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Frequently asked questions
Is this an exact bow setting?
No. It is a starting estimate that needs a practical fitting.
Can I use height instead of wingspan?
Measure wingspan. Height and wingspan are similar for some people but not identical.
Should I round the result?
The result stays unrounded internally. A bow technician can choose an available setting after checking your form.