What is Draw Length? Draw Length is the distance from nock point to the throat of the grip plus 1 “.

Unlike a traditional recurve bow that can be drawn back to virtually any length, a compound bow will draw back only a specific distance before it stops (hits the wall).
So if a compound bow is set to a draw length of 28” it should always be shot from the full 28" draw position. But the bow cannot be over-drawn, say to 29" or 30", without modifying the setup on the bow. That is why when you buy a compound bow it needs to be set to your specific draw length.

How To Determine & Measure Draw Length-female-drawlength-jpgTo measure your draw length, determine the length of your arm-span in inches. Stand with your arms out and palms facing forward. Don't stretch when measuring. Just stand naturally. Have someone else help you, and measure from the tip of one middle finger to the other. Then simply divide that number by 2.5. The quotient is your proper draw length (in inches) for your body size.

How To Determine & Measure Draw Length-male-drawlength-jpgDon’t be like most people and set your draw length too long. This will result in poor shooting form, inaccuracy, floating anchor point, and yes that painful and I do mean painful string slap on the forearm. You will better enjoy - and be more successful with your new bow when it is fitted properly to your body. And REMEMBER! If in doubt, choose a little LESS draw length rather than a little more.

The following charts give an example of average draw lengths based on height. There is often a direct correlation between the tow but you should ALWAYS MEASURE your draw length rather than using this chart alone. This chart can be used to double check your calculations.

LONG DRAW SHOOTERS:
How To Determine & Measure Draw Length-drawlengthscalelong-jpg (click to enlarge)
SHORT DRAW SHOOTERS:
How To Determine & Measure Draw Length-drawlengthscale-short-jpg (click to enlarge)

So now you have learned the foundations and basics on how to measure and determine your draw length. Your bow is set up perfectly to match these measurements and calculations but it just doesn't feel right.
Your own "perfect draw length" is the draw length setting at which you are the most comfortable and the most accurate. For some, a "perfect draw length" may be ultimately determined by feel (and some trial and error) rather than by calculation.

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Further Considerations on Draw Length

Anchor Point:

How To Determine & Measure Draw Length-anchor-reference-jpg(click to enlarge)
A properly set draw length helps you to establish reference points at full-draw - key elements to reliable accuracy. When you come to full draw, you will want to establish contact points between you and the bow. Hopefully, these points will be the same every time you draw the bow. Perhaps you'll concentrate on where your knuckle meets your ear or cheek (1), perhaps how the string touches the corner of your mouth (2), or how the tip of your nose just tickles the string below the peep (3).
You may choose to use a kisser button and set it to come back and touch the corner of your mouth. Whatever reference points you choose to monitor is up to you, but they are an important part of a consistent routine and collectively help you to establish your ANCHOR POINT for each shot. If you don't release each shot from the exact same ANCHOR POINT, your accuracy will always be mediocre at best.

Peep Sight:
Too Far From Peep How To Determine & Measure Draw Length-peep-short-jpg Correct Distance How To Determine & Measure Draw Length-peep-correct-jpg Too Close to Peep How To Determine & Measure Draw Length-peep-jpg

Perhaps the most critical alignment is that between your eye and your peep sight. The proper distance is anywhere from 4 to 6”. If you're too far away from the peep sight (draw length too short) then your field of view through the peep is too restricted. Seeing too little inside the peep, and too much outside your peep makes acquiring your target very difficult - even in broad daylight - and next to impossible in low light conditions.
If you're too close to the peep sight (draw length too long), you get a different set of problems. As objects are moved very close to your eye, into your eye's Field of Proximal Convergence, your eyes naturally begin to cross (even if you have one eye closed). It's very difficult to "un-train" your eye react to this involuntary reflex - so sighting will always seem unnatural and strained when the peep is too close to the eye.

String Loop:
Does a string loop actually change the bow's draw length? Certainly not. Remember the specs above for measuring draw length. (Draw Length is the distance from nock point to the throat of the grip plus 1 “.) Reference the actual bowstring at it's nocking point. So adding a string loop to a 29" bow DOES NOT make the bow a 29.5" draw length. However, a string loop might make it seem that it changes your draw length since you will have to draw the string further back.
Look at the diagrams below. This is the same bow, at the same draw length, drawn back first without and then with a string loop. Notice the pink lines referencing the relative positions of the crease of his index & middle finger to his ear. Clearly you can see that when using the string loop, his hand decidedly rests further back on his jaw (perhaps as much as an inch further back). But the distance between his eye and the peep sight, as well as the contact between his nose and string both remain the same.
No Loop How To Determine & Measure Draw Length-loop-jpg With Loop How To Determine & Measure Draw Length-loop-jpg