Draw length is the distance from the nock of the arrow to the back of the bow when the bow is fully drawn, and it decides three things before you spend anything: how long the bow should be, how long the arrows should be, and what the number on the limb will actually feel like in your hand.

You can get it close at home from one measurement, your wingspan, which is the same as your arm span taken fingertip to fingertip. The calculator does the same arithmetic a shop does at the counter. It is a ballpark rather than a measurement, so treat the result as the size to shop in, not the size to cut arrows from without a second look.

Draw Length and Bow Size Calculator

Your wingspan in, or your height if you do not know it. Four numbers out, from the same arithmetic the guides use.

lb at your draw, if you already know it
Nock groove to the deepest part of the grip, plus 1.75 in
Your draw length
–
Bow length
–
Arrow length
–
Label to look for
–

The last tile is the limb label that pulls your target weight at your draw. Leave the target blank and it reads 30 lb, which sits in the middle of the range most adults start in. Start lighter if you are unsure.

Wingspan to Draw Length Chart

This is the same division the calculator runs, worked out for every span from 54 to 83 inches. Find your wingspan in the left column and read across. Every figure is rounded to the nearest half inch, which is about the precision a bow size can actually use.

Your wingspan Estimated draw length
54–56 in137–142 cm 21.5 to 22.5 in
57–59 in145–150 cm 23 to 23.5 in
60–62 in152–157 cm 24 to 25 in
63–65 in160–165 cm 25 to 26 in
66–68 in168–173 cm 26.5 to 27 in
69–71 in175–180 cm 27.5 to 28.5 in
72–74 in183–188 cm 29 to 29.5 in
75–77 in190–196 cm 30 to 31 in
78–80 in198–203 cm 31 to 32 in
81–83 in206–211 cm 32.5 to 33 in

Two charts will not always agree. When another source gives you a number an inch or so off this one, the difference is usually the formula behind it, or the AMO convention explained further down. Neither makes your span reading wrong. Outside 54 to 83 inches, use the calculator at the top of the page.

How to Measure Your Wingspan

Two inches of error here moves you a whole bow length, so it is worth doing twice.

  1. Stand with your back against a wall, shoes off, heels and shoulder blades touching it.
  2. Hold both arms out level with the floor, fingers straight, palms facing forward. This is your wingspan, and it is the only measurement the calculator needs.
  3. Get someone to mark the wall at the tip of each middle finger. Measuring this alone is where most bad numbers come from, because one arm drifts forward.
  4. Measure between the marks. Repeat it. If the two differ by more than half an inch, take a third and use the middle one.

If nobody is around, stand in a doorway and mark the frame with tape at each fingertip, then measure the tape. It is slower and a little less accurate, which is exactly why the calculator rounds.

The Arithmetic Behind the Calculator

Every figure below is a rule our own bow guides already use. None of them is a standard published by a governing body, which is why a shop measuring you at full draw still wins. If the calculator is unavailable, this table does the same job.

DrawBowArrows30 lb bow
24 in62 to 64 in25 to 26 in20 lb
25 in63 to 65 in26 to 27 in22.5 lb
26 in64 to 66 in27 to 28 in25 lb
27 in65 to 67 in28 to 29 in27.5 lb
28 in66 to 68 in29 to 30 in30 lb
29 in67 to 69 in30 to 31 in32.5 lb
30 in68 to 70 in31 to 32 in35 lb
31 in69 to 71 in32 to 33 in37.5 lb
32 in70 to 72 in33 to 34 in40 lb

Reading across: your draw length, the bow length to buy, the arrow length to order, and what a bow marked 30 lb at 28 inches actually pulls at that draw. Draw length is wingspan divided by 2.5. Bow length is draw length plus 38 to 40 inches. Arrow length is draw length plus 1 to 2 inches, as most pro shops cut them, and it is a separate decision from arrow spine: the arrows and broadheads guide covers spine, grain weight and FOC. Draw weight is measured at 28 inches and climbs about 2 to 3 lb for every extra inch, so the last column uses 2.5 lb. The same rules are set out in the traditional bows guide and the starter kit guide.

The Second Formula, and Why It Gives a Different Number

A fair number of sources give draw length as (wingspan − 15) ÷ 2 instead of wingspan ÷ 2.5. Both are in use, and on the same body they land close together without landing on the same number.

Your wingspan ÷ 2.5 → (span − 15) ÷ 2
66 in 26.4 in → 25.5 in
69 in 27.6 in → 27.0 in
72 in 28.8 in → 28.5 in
75 in 30.0 in → 30.0 in
78 in 31.2 in → 31.5 in

The two agree exactly at 75 inches and disagree on either side of it. Below 75 the second formula runs low, above it runs high, because you are taking a fixed 15 inches off a span that keeps growing.

We use wingspan ÷ 2.5 here, because it is the one our traditional and recurve sizing pages were built on and the one most charts start from. If a source hands you a number a half inch or an inch off ours, check which of the two it used before deciding either is wrong.

Signs You Are Drawing the Wrong Length

These show up long before a group size tells you anything, and most of them are about where your body ends up rather than where the arrow lands. If two or three sound familiar, re-measure before you order arrows.

Too long
  • The nock sits in front of your face instead of against it, and you cannot find the same spot twice.
  • Your front shoulder creeps up toward your ear at full draw.
  • You tip your head forward, or bend the bow arm, to reach anchor.
  • You get more string slap than the people beside you.
Too short
  • You cannot reach the corner of your mouth or your jaw without straining.
  • Your bow arm is still bent at full draw and your back never takes the load.
  • The first shot feels fine and the sixth is shaky.
  • Your drawing elbow points at the floor instead of back.

What right feels like is easier to describe than to measure: front shoulder down, bow hand relaxed, the hold carried by your back, and two seconds at full draw without the hand shaking. If the last one fails, the number on the calculator is not your problem. If string slap is what sent you looking, the arm guard guide covers the fix.

What the Calculator Cannot Know

Four things sit outside the arithmetic, and all four are the reason a shop still measures you.

  • The way you actually shoot. A thumb draw, as on a horse bow, and a deep anchor both move the measurement away from the estimate. Neither is built into it.
  • Your strength. Nothing here measures it. The weight that suits you is the one you can draw, hold for a few seconds and let down without shaking, and that is usually lighter than the limb label suggests.
  • A compound bow. Its draw length is set by the cam or the module and adjusted by a shop. This arithmetic is for traditional bows, recurves and longbows. Our recurve sizing guide covers the recurve side in more detail, and the compound bow guide covers how draw length is set on a compound once you have it in your hands.
  • Growth. A child’s span changes every year, so buy a takedown and swap the limbs. The youth bow guide gives the weight ranges by age.

One more: form moves the number. Many beginners find their draw length changes by half an inch after a few weeks, once the anchor settles. Re-check before buying a second bow rather than assuming the first number was wrong.

AMO Draw Length, and Why Your Three Numbers Do Not Match

Three different measurements get called your draw length, and most of the confusion about this topic comes from mixing them.

The numberWhere it is measured
AMO draw lengthNock groove to the throat of the grip, at the deepest part of the handle, plus 1.75 inches. This is the number people mean when they ask for your draw length.
What you measure on the bowNock groove to the grip or the arrow rest, without the 1.75 inch allowance. It comes out shorter than AMO by exactly that much.
Arrow lengthThroat of the nock to the end of the shaft, no point and no insert. Most spine charts are read from this number, not from draw length.

A shooter on r/Archery laid the three side by side: 28 inches from nock to rest, a 29 inch shaft, and an apparent draw length of 30. None of those numbers was wrong and all three were the same archer. If a chart asks for draw length, give it AMO. If it asks for arrow length, do not convert, because the chart is already measuring the shaft.

Frequently Asked Questions

Questions about the measurement itself. For which bow to buy with the numbers, the traditional bows guide covers types, weights and stacking.

Measure your wingspan and divide by 2.5. A 70 inch span gives 28 inches, and a 75 inch span gives 30. Stand against a wall with your arms out level, mark the wall at each middle fingertip, and measure between the marks. Repeat it once, because doing it alone is the usual source of an inch of error. Our recurve sizing guide explains what to do with the number.

Enough to choose a bow size, not enough to cut arrows. The method has to assume where you anchor, and a shop measures you at full draw instead, so the two numbers rarely land on the same half inch. Arrows are cut to your draw length and an inch of error gives you shafts you cannot use, so buy the bow in this size and let the shop cut them to you.

68 to 70 inches for a recurve or longbow. The rule is draw length plus 38 to 40 inches. Going shorter than that is where stacking starts: the weight climbs sharply near full draw and the string angle pinches your fingers.

30 to 31 inches. Shops cut arrows one to two inches past the draw length so the point stays clear of the bow at full draw. If you plan to change your anchor or shoot a thumb draw, say so before the shop cuts them, because length cannot be added back. Length is not spine: a bow with no arrow rest and no clicker bends the arrow around itself, so spine is the number that decides whether the shaft flies straight. See the arrows guide.

Because the 30 lb was measured at a 28 inch draw and you probably draw longer. A bow gains roughly 2 to 3 lb for every extra inch, so 30 lb at 28 inches is about 35 lb at 30 inches. That is normal, and it is the single most common surprise when a new archer picks up a bow marked to a standard they did not know about.

Up. A longer bow is smoother and more forgiving at the same draw weight. A bow shorter than your draw stacks, which costs you both comfort and accuracy. Length is also the one thing you cannot adjust later, unlike draw weight on a takedown.

No. A compound bow’s draw length is set by its cam or its draw-length module, and a shop changes it by fitting a different module. Wingspan gives you a starting point for a compound too, but the bow is then configured to you rather than bought in a length. The compound bow guide covers that side.

It can. A deeper anchor, a more consistent release and a settled shoulder position often add or remove half an inch in the first few months. Measure again before a second bow purchase, and do not assume your instructor’s number from day one is final.

Yes, less accurately. Stand in a doorway and put a piece of tape on each side of the frame at your middle fingertips, then measure across. That is your wingspan, not half of it. Reading a tape while holding both arms out is the method that produces wrong numbers, so the tape on the frame is worth the extra minute.

About 2 to 3 lb. Shortening your draw lowers the weight the same way. This cuts both ways when you shop: a bow marked 35 lb is a light bow for a 26 inch draw and a heavy one for a 31 inch draw.

Use the same wingspan rule, but ignore what it says about weight. Children should start lighter than the adult range and move up as they grow, which is why a takedown with swap limbs costs less over five years than two one-piece bows.

It will, and the number is not wrong. A thumb draw with a horse bow changes where the string sits on the hand and how far back the anchor goes. Measure the arrow instead: if the point sits behind the back of the bow at full draw, the arrows are too short regardless of what the calculator said.

Only as a rough stand-in. Adult wingspan usually sits within a couple of inches of height, so height divided by 2.5 lands near the wingspan answer, and near is all it is. A 5 foot 10 adult comes out at 28 inches, which is the right size to shop in. The number to cut arrows by still has to come from a span measurement, or from a shop that measures you at full draw.

29 inches, which pairs with a 67 to 69 inch bow and 30 to 31 inch arrows. The arithmetic is wingspan divided by 2.5, rounded to the nearest half inch, so any span from 72 to 73 inches lands on 29 inches. Measure the span twice before anyone cuts shafts.

Because they are three different measurements. Draw length is the nock groove to the throat of the grip plus 1.75 inches, which is the AMO standard. Arrow length is nock to the end of the shaft, with no point and no insert. A shooter measuring 28 inches to the rest and holding a 29 inch shaft is not confused; the numbers are answering different questions. Give a spine chart the arrow length and a bow shop the AMO number.

Front shoulder stays down, the bow hand stays relaxed, your back carries the hold, and you can stop at full draw for two seconds without the hand shaking. If the nock will not sit in the same place twice, the number is usually the problem rather than your form. Re-measure before changing anything else, because half an inch is enough to move a bow one size.

1.75 inches. AMO draw length runs from the nock groove to the throat of the grip and then adds 1.75 inches. The actual measurement stops at the grip and adds nothing. On the same bow the AMO figure is always the longer one, which is why a bow measuring 26.25 inches to the grip gets sold as 28 inches of draw. Shops quote AMO because bow specifications are published that way. If you measure a bow you already own and leave the 1.75 out, you will land about an inch and three quarters below the calculator. Neither number is wrong.
The arithmetic does not set a limit. The bow does. At 32 inches of draw the sizing rule puts you on a 70 to 72 inch recurve, and at 33 on a 71 to 73 inch bow. Our sizing table stops at 31 inches of draw and a 69 to 71 inch bow, because past that the length stops being a size you pick and becomes a build you specify. The rule itself does not change above 31 inches, it just lands outside the table. At that length, limb length and draw weight matter more to how the bow feels than the number on the label.

Where the Four Numbers Go Next

Bow length

Take the range from the calculator and compare it against the bows we make, with traditional and recurve sizes listed separately. See the bow sizes.

Arrows

Draw length plus 1 to 2 inches is your arrow length. The arrow and broadhead guide covers which spine goes with each length. Open the arrow guide.

Arm guard

Where the string meets your forearm is set by your draw length, so check the sizing on that page rather than buying the first guard you see. Check the sizing.

A bow cut to your numbers

Send us the four numbers and we will confirm the size before anything is cut. Send the numbers.

Shooting already, and want gear cut to your numbers?

Quivers, bow bags and arm guards made to order, one piece or a hundred, with names and club crests worked in. The calculator gets you the bow size. The quote tells you what the rest costs.

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