📐

Bow Draw Length Calculator

Don't know your draw length yet? Enter your wingspan and get three estimates (÷2.5, ÷2.6, AMO) plus an arrow-length recommendation sized to your bow type — the upstream question before arrow length.

Total Steps

📏

Tape · DL Arrow

~10m

Est. Duration

Draw Length Calculator

Wingspan (fingertip to fingertip)

≈ 71.0″

Bow Type

Arrow-Length Safety Margin — 0.75″ (+0.5″ to +1.0″)

÷ 2.5 Method

28.40″

÷ 2.6 Method

27.31″

AMO Standard

28.5″

Recommended Arrow Length (Compound Bow)

29.3″ (29.0–29.5″ range)

Draw length (AMO) = nock-groove to throat-of-grip + 1.75″. Arrow length = DL + bow-type margin so the broadhead clears the rest safely. Verify with a calibrated DL arrow before cutting a dozen.

The Upstream Question: What Is Your Draw Length?

The arrow length calculation guide assumes you already know your draw length and converts it to a cut length. But many archers arrive not knowing their draw length at all — they need to measure it first, then derive the arrow length. This calculator is for that upstream step: enter your wingspan, get draw length three ways, then read off the arrow length your bow type wants.

Draw length is a body-and-bow measurement that does not change per arrow. Arrow length is a build decision you tune per setup, sized from the draw length plus a bow-type safety margin. Getting draw length wrong is the single most common cause of poor shooting form — a draw set even ½″ too long forces you to lean back and hunch your shoulder to reach the anchor, and a draw set too short starves the bow of power-stroke energy. Measure once, correctly, and every subsequent number (spine, speed, kinetic energy) lands right.

Draw Length Selection SOP — 5 Steps

Follow the steps in order. Each is a decision node — check it off when complete. The progress bar tracks your position through the selection wizard.

Progress0/5 steps · 0%

Step 1: Measure wingspan

Decision Point

Stand with arms stretched flat to the sides, palms facing forward. Have a partner measure fingertip-to-fingertip across your back (typical adult: 64–76″). Do not stretch or round the shoulders — a neutral, relaxed posture gives the true span.

Step 2: Compute draw length (3 methods)

Decision Point

Divide wingspan by 2.5 (ATA simplified), by 2.6 (conservative), and apply AMO rounding to the nearest ½″. The calculator above returns all three. For most compound shooters the AMO number is the one to set the cam stops to.

Step 3: Verify with wall method or DL arrow

POC Stage

Cross-check the wingspan estimate: use the fist-to-wall method solo, or — best — draw a calibrated DL arrow to anchor at a bow shop. If the DL-arrow reading differs from the ÷2.5 estimate by more than 0.5″, trust the DL arrow and reset the cams.

Step 4: Convert to arrow length by bow type

Decision Point

Add the bow-type margin: compound +0.5–1.0″, recurve +1.5–2.0″, traditional +1.5–3.0″. Crossbow is rail-fixed at 20–22″ — never deviate. The bow-type table below gives the rationale for each.

Step 5: Safety check (over/under length)

POC Stage

At full draw, confirm the arrow tip clears the rest by ≥0.5″ (too short = the arrow can fall off and deflect off the riser — a safety hazard). Confirm the cut length does not over-stiffen dynamic spine (too short = tail-left paper tear). Paper-tune before committing a dozen.

How to Measure Draw Length — Three Field Methods

The calculator automates the math, but you still need a real-world measurement to feed it. These are the three methods archers and bow shops actually use, ranked from quickest to most accurate.

Wingspan ÷ 2.5 (ATA simplified)

Accuracy: ±0.5″

DL = wingspan ÷ 2.5

Stand arms flat, palms forward; measure fingertip-to-fingertip across the back; divide by 2.5.

Industry-standard shortcut used by most bow shops and online calculators.

Wingspan ÷ 2.6

Accuracy: ±0.5″

DL = wingspan ÷ 2.6

Same wingspan measurement; divide by 2.6 for a marginally shorter, more conservative result.

Preferred by some recurve shooters and for a slightly shorter 'true' draw feel.

AMO / ATA formal (pivot + 1.75″)

Accuracy: ±0.25″

DL_AMO = (wingspan ÷ 2.5), rounded to ½″ increments

Define DL as nock-groove to throat-of-grip + 1.75″; measure with a calibrated DL arrow at full draw.

The formal standard. Rounds to the half-inch cam modules bows are sold in.

Wall (fist-to-wall) method

Accuracy: ±0.5″

DL = fist-to-wall distance − 0.5″

Stand sideways, fist against wall; measure wall to mouth corner; subtract 0.5″.

Quick solo measurement without a partner to run a tape across your chest.

DL arrow (draw-length indicator)

Accuracy: ±0.1″

DL = direct reading from a calibrated DL arrow

Draw a purpose-built graduated arrow to anchor; read the number off the shaft.

Gold standard, used by bow shops for final cam-stop tuning.

💡 Assessment Tip

90% of self-measured draw lengths are wrong because the archer stretches or rounds the shoulders. Measure relaxed — a neutral posture, not a stretched one, gives the true span.

⚠️ Data-Inflation Warning

A wingspan that looks “good” because you stretched adds a false 1–2″ to the draw length, which then over-stiffens the spine and drops the speed calculation. Don't trust a stretched measurement.

❌ Selection Mistake

Never set draw length from the bow's marketing “30-inch” default. Most adults are 27–29″ — running a 30″ module on a 28″ draw forces the lean-back, hunched-shoulder form that ruins accuracy.

Arrow Length — Too Short Is Dangerous, Too Long Is a Tuning Problem

Cutting the arrow is irreversible, so the safety margins matter. An arrow that is too short can fall off the rest at full draw and deflect off the riser — a genuine injury hazard. An arrow that is too long adds mass (slower), weakens dynamic spine (tail-right tear), and may contact the bow window. The diagram shows the safe window.

Draw Length → Arrow Length by Bow Type

Once you have your draw length, the safety margin to add depends on the bow. Compound arrows are shortest (cam stops fix the draw); recurve and traditional need more length past the rest; crossbows are rail-fixed. The calculator applies the matching margin automatically when you pick a bow type.

Bow Type	Margin over Draw Length	Rationale	Typical Arrow Length
Compound Bow	+0.5″ to +1.0″	Cam stops fix draw length; arrow only needs to clear the berger hole and rest. Shorter = faster + stiffer dynamic spine.	26–30 inches
Recurve Bow (Olympic)	+1.5″ to +2.0″	Clicker sits 1–2″ past the rest; arrow must extend past clicker at full draw to allow clicker drop.	28–32 inches
Traditional Longbow / Recurve	+1.5″ to +3.0″	No rest shelf constraint; arrow sits on the back of the bow hand and must extend past it for clean release.	28–32 inches
Crossbow	rail-fixed	Bolt length is fixed by the rail — typically 20–22″. Too short = dry-fire risk; too long = jam. Never deviate from manufacturer spec.	20–22 inches

Bow and Arrow Size Chart — Draw Weight × Draw Length → Arrow Length & Spine

This bow and arrow size chart pulls together every sizing dimension an archer needs in one place: draw weight, draw length, recommended arrow length, and the matching spine grade. Use it as a quick-reference when you are shopping arrows or matching a hand-me-down dozen to a new bow. For the exact draw length number behind each row, run the calculator above; for spine-only detail, jump to the Arrow Spine Chart.

Draw Weight	Typical Draw Length	Recommended Arrow Length (Compound)	Matching Spine (Compound)	Typical Use
25–35 lb	24–26″	25–27″	600	Youth, beginner, light target
35–45 lb	26–28″	27–29″	500	Youth hunting, women's target, light recurve
45–55 lb	27–29″	28–30″	500–400	Light hunting, recreational target
55–65 lb	28–30″	29–31″	400	Most common hunting setups, 3D archery
65–75 lb	29–31″	30–32″	340	Standard 70 lb compound hunting setup
75–85 lb	30–32″	31–33″	300	Heavy hunting, aggressive-cam speed bows
80+ lb / crossbow	30–34″ (rail)	20–22″ (rail-fixed)	250	Flagship speed bows, dangerous game, crossbows

The chart assumes a 100 gr point and a moderate cam — step stiffer (smaller spine number) for aggressive cams or 125+ gr points. Recurve shooters step one grade weaker (larger number) at the same draw weight because a finger release loads the shaft more gently.

Draw-Length Misjudgment Self-Test

Your body tells you when the draw length is wrong. If you see any of these symptoms at full draw, the draw length — not the arrow, rest, or broadhead — is the likely culprit.

Draw length too LONG

Leaning back / head craning forward at full draw

Shorten ½″ — your body is compensating to reach the anchor.

Draw length too LONG

Front shoulder hunching up toward the ear

Shorten ½″ — the shoulder is rising to seat the string at anchor.

Draw length too LONG

Elbow hyperextends / locked and painful at release

Shorten ¼–½″ — the draw is over-stretching the shoulder joint.

Draw length too SHORT

Cannot reach a solid anchor against the face

Lengthen ½″ — you are running out of draw before the anchor locks.

Draw length too SHORT or elbow rotation

String hits the inside of the elbow / forearm slap

Lengthen ¼–½″ and rotate the elbow; short draw drops the string path onto the forearm.

Draw length too SHORT (under-drawing)

Pin groups string low at distance beyond 30 yards

Lengthen ½″ — short draw reduces power-stroke energy, dropping arrow speed.

Your draw-length build card — copy to your notes

# Draw length & arrow length build card
wingspan        = 71 inch  (71.0 inches)
---
draw_length     = 28.40 in   (÷2.5 ATA simplified)
                = 27.31 in   (÷2.6 conservative)
                = 28.5 in   (AMO rounded to ½")
bow_type        = Compound Bow
arrow_margin    = 0.75 in
arrow_length    = 29.3 in
recommendation  = verify with DL arrow, then paper-tune before cutting a dozen

Frequently Asked Questions

How do I calculate my bow draw length from my wingspan?▼

Measure your wingspan fingertip-to-fingertip across your back with arms out flat, palms forward. Divide by 2.5 for the ATA simplified method, or by 2.6 for a slightly shorter conservative result. The AMO/ATA formal method is the same ÷2.5 number rounded to the nearest half-inch, defined as nock-groove to throat-of-grip plus 1.75 inches. The calculator above returns all three from a single wingspan entry. Example: a 71-inch wingspan gives 28.4″ (÷2.5), 27.3″ (÷2.6), and 28.5″ (AMO rounded).

What is the difference between draw length and arrow length?▼

Draw length is a body-and-bow measurement: the distance from the nocking point to the pivot of the grip plus 1.75 inches (AMO). It does not change per arrow. Arrow length is a build decision: the physical length of the arrow from nock groove to tip apex, which you cut per setup. Arrow length is usually 0.5–1.0 inch LONGER than draw length on a compound (so the arrow clears the rest), 1.5–2.0 inch longer on an Olympic recurve, and rail-fixed on a crossbow. Use this calculator to find draw length first, then read the bow-type table for the arrow-length margin.

How do I use this as an arrow length calculator?▼

Enter your wingspan to get draw length, then pick your bow type — the calculator adds the correct safety margin (compound +0.5–1.0″, recurve +1.5–2.0″, traditional +1.5–3.0″) and returns your arrow length range. If you already know your draw length and only want the arrow-length conversion, the bow-type table and the arrow-length chart section below give the margins directly. For the full first-principles arrow-length derivation, read the arrow length calculation guide.

Is there an arrow length chart by wingspan and bow type?▼

Yes — an arrow length chart is a pre-computed lookup of Draw Length = Wingspan ÷ 2.5, then Arrow Length = DL + bow-type margin. Common wingspan rows read: 64″ wingspan = 25.6″ DL → 26.1–26.6″ compound; 68″ wingspan = 27.2″ DL → 27.7–28.2″ compound; 71″ wingspan (adult male median) = 28.4″ DL → 28.9–29.4″ compound; 74″ wingspan = 29.6″ DL → 30.1–30.6″ compound. Always verify against the manufacturer's published minimum safe arrow length for your exact shaft model before cutting.

Which draw length method is most accurate?▼

The DL arrow (draw-length indicator) at ±0.1″ is the gold standard, followed by the AMO formal method at ±0.25″. The wingspan ÷ 2.5 shortcut is accurate to ±0.5″ for average builds but drifts for very tall or short archers. For final cam-stop positioning, a bow shop should confirm the wingspan estimate with a calibrated DL arrow. Use the ÷2.6 divisor if you want a slightly more conservative (shorter) number for recurve.

What happens if my draw length is set too long?▼

A draw length that is too long forces you to lean back, crane your head forward, or hunch your front shoulder up toward your ear to reach the anchor — all of which destroy shot consistency and can strain the shoulder joint. A long draw also causes the elbow to hyperextend at full draw. Shorten in ½-inch increments until your anchor locks with a relaxed, neutral posture and a level front shoulder.

How does draw length affect arrow speed and spine?▼

Every inch of draw length adds roughly 10 fps of arrow speed (more power stroke) and loads the shaft harder, weakening dynamic spine by about half a spine grade. A 70 lb bow at 32″ draw wants a 300 spine where the same bow at 28″ is happy at a 340. Always re-run the arrow speed and spine calculations after a draw-length change — they move together.

Can I measure draw length by myself without a partner?▼

Yes — use the wall (fist-to-wall) method: stand sideways against a wall, fist against the wall, and measure from the wall to the corner of your mouth, then subtract 0.5 inch. It is accurate to ±0.5″ and needs no partner. For the most accurate solo number, a graduated DL arrow drawn to anchor is better, but the wall method is sufficient for an initial setup before a bow-shop confirmation.

Is there an arrow length to draw length chart (reverse lookup)?▼

Yes — the reverse direction of the arrow length chart. If you already have an arrow cut to a known length and want to back out the draw length it implies, subtract the bow-type margin first: Draw Length = Arrow Length − margin (compound −0.5 to −1.0″, recurve −1.5 to −2.0″, traditional −1.5 to −3.0″). So a 29″ compound arrow implies a ~28–28.5″ draw length; a 30″ recurve arrow implies a ~28–28.5″ draw length. Then divide your wingspan by 2.5 to confirm — the two numbers should agree within ½″. Use the arrow-length-by-bow-type table and the bow-and-arrow size chart above as the forward arrow length to draw length chart: read across each row to see which draw length a given arrow length corresponds to, in both directions.

From Draw Length to a Full Build

Draw length is the foundation number — get it right and the rest of the build follows naturally. Once you have it, the next steps are picking a spine and verifying energy: use the Arrow Spine Chart to match a shaft to your draw weight (remember, every +1″ of draw length weakens dynamic spine by about half a grade), then run the Arrow Kinetic Energy Calculator with your finished arrow weight and speed to confirm ethical energy for your target game.

To convert a known draw length straight into an arrow cut length — the downstream step once draw length is settled — read the arrow length calculation guide. And when you are ready to compute real arrow speed from your bow's IBO rating and these draw parameters, the homepage arrow speed calculator ties everything together.