How To Calculate Draw Length For Compound Bow

How To Determine Draw Length — Shooting the correct draw length is extremely important to maximizing your accuracy.

What Is Draw Length?

Draw length is exactly as the term describes, it is the length (in inches) that a bow is drawn. This length is measured from the front of the Berger hole (where the arrow rest mounts to the riser) to the corner or angle of the string.

This can also be measured from the front most part of the grip to the corner of the string .

On compound bows, each bow is set at a particular length and the bow should always be fired from that set length. Recurve bows and longbows don't have a set draw length and can be fired from virtually any length the archer chooses.

Why Is Draw Length Important?

Importance of proper draw length should never under estimated as it is crucial to proper form and accuracy in archery.

With a correct draw length most shooters will be able to maximize their draw weight which is especially important to bow hunters since this directly affects the speed of a bow.

The IBO speed that is advertised for bows is measured at a 30" draw length, when the draw length is shortened the bow will lose speed, the opposite is also true.

With that said, it is important that shooters use the proper fitting draw length and not try to shoot a longer draw length to gain more speed.

How To Measure Draw Length

How To Determine Draw Length

Several methods exist to figure out proper draw length; some of them are accurate, many are not. Most archery shops will have a draw length check bow that has a faux arrow with measurements marked.

The shooter draws the bow and the draw length is indicated by the markings on the arrow. This method is plenty accurate assuming a couple of things.

First, it is important that the shooter uses proper form, this means the arm holding the bow is slightly bent, not a locked out elbow.

Secondly, it is important that the string is only drawn to the corner of the mouth, any further and your draw length will be too long.

For the people that don't have a shop close by or prefer to figure out their draw length on their own, there is a fail-safe method that only requires a tape measure and a calculator.

To do this the shooter being measured should stand with his/her back against the wall and measure the wingspan (tip-to-tip of the fingers).

Make sure the palms are forward, not against the wall and that the shooter isn't stretching.

When the measurement is found (in inches), divide that number by 2.5 and the resulting number will be proper draw length. For instance, my wingspan is 72.75 inches, so 72.75/2.5 is 29.1" and I shoot a 29" draw length.

For almost all shooters, this method is very accurate and the most simple route.

String Loops & Draw Length

How To Determine Draw Length

Many people wonder whether or not a D-loop or string loop increases draw length. Since we know that compound bows are set to a particular length, the technical answer is no. However, adding a ½ inch D-loop does increase the length of pull for the shooter.

If a shooter is at their maximum draw length, it is possible that a string loop could put them out of their comfortable range.

For example, some archers who measure for a 29″ draw length prefer to shoot a 28.5″ bow with a string loop and release.

It is important to make sure the bow you are shooting is set properly for your draw length and feels comfortable while you are shooting it.

Adjusting Draw Length

Many bows feature an adjustable draw length which may span several inches and is adjusted in 1/2″ increments. However other bows have draw length specific cams which means if you want to adjust the draw length a new cam must be installed.

It is important to consult with a trained bow technician before attempting to adjust the draw length of your bow.