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Archery Draw Length Calculator (Arm Span ÷ 2.5)

Find your bow draw length from your arm span with the archery wingspan ÷ 2.5 rule, plus the compound bow setting and a suggested arrow length, in centimeters or inches.

Units

Arm span (wingspan)

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How it works

Draw length = arm span ÷ 2.5 · compound setting = draw length in inches rounded to the nearest ½ in · arrow length ≈ draw length + 1 to 2 in (2.5–5 cm).

Draw length is the distance from the nock point on the string to the pivot point of the grip (plus 1¾ in, by the AMO/ATA standard) at full draw. The quickest way to estimate it is to measure your arm span, fingertip to fingertip, and divide by 2.5 — the rule used by archery shops and bow makers. Compound bows are set in half-inch steps, so round to the nearest ½ inch and confirm at full draw with a draw-check arrow; an overlong draw ruins form and slaps the forearm.

Worked example

An archer with a 175 cm arm span: draw length = 175 ÷ 2.5 = 70.0 cm (27.6 in). A compound bow would be set to 27.5 in, and arrows of about 72.5–75.1 cm (28.6–29.6 in) leave a safe margin past the arrow rest.

Sources: Archery 360 — How to determine your draw length · Easton Archery — Arrow selection and draw length

Frequently asked questions

How do I measure my draw length?

Stand with your arms straight out to the sides, palms forward, and have someone measure from middle fingertip to middle fingertip. Divide that arm span by 2.5. For a 70-in span that is 28 in.

Can I use my height instead of arm span?

Yes, as a rough guide: arm span is usually within a few centimeters of height, so height ÷ 2.5 gives a close starting point. A pro shop can then confirm at full draw.

What happens if my draw length is too long?

You over-extend the bow arm, lose anchor consistency and are more likely to get string slap on the forearm. Too short a draw cramps your form and wastes arrow speed. Archers usually err slightly short.

How long should my arrows be?

For safety, arrows should extend 1–2 inches (2.5–5 cm) past the arrow rest at full draw, so add about 1–2 in to your draw length, then confirm with your bow setup and spine chart.

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This calculator is for educational purposes. Double-check important results before acting on them.