How To Measure A Compound Bow String (2-Method Guide)

By Andy Ryan


Updated at
a man holding his compound bow

Bowstrings are incredibly important. Essentially, your bow is pointless without the strings, and if you don’t attach it carefully, your strings could be to blame for bad shooting and accuracy.

Knowing a few basic tactics on how to measure compound bow string length correctly can come in handy. It is an essential skill, especially if you want to ensure that your compound bow is precisely tuned and ready to fire. This article is a step-by-step guide on measuring a compound bow strings length:

Cables and Strings on Compound Bows

Compound bows feature rigid limbs. They are substantially more complicated than conventional bows because of their cams, axles, pulleys, cables, and strings. Compound bows are built to provide archers a tactical advantage over other bows. Compound bows provide significantly greater force, causing the arrow to fly ahead with far more acceleration. 

I want you to remember that bowstrings are distinct from the bus cable and control cable, both present on a compound bow. You will see that the axles are linked to the bus cable and the cams links to the control cable. As you check them, you will see that control cables have serving ends. Subsequently, cables are attached to the cable sliders, but the bowstring is not.

The Connection Between The Bowstring and Draw Length

You can determine the length of your bowstring once you know your draw length. Here’s the guide on how to measure draw length. Naturally, the draw length of a compound bow refers to the distance between the arrow rest and the maximum arm span when you pull back the arrow at full draw.

You wouldn’t want the bowstring to be too long since you won’t be able to provide the force intended to shoot the arrow. However, you wouldn’t want it to be too stiff because it will be tough to pull the arrow back. As a result, determining the proper bowstring length for your bow is essential.

What Should Be The Proper Bow String Length?

Most compound bow owners let the bow’s manufacturer or a sports equipment store specialist assess the string length for them. However, knowing the criteria for your specific bow is extremely useful. Since your bow most likely comes with strings, you may simply utilize that length. Use a tape measure and measure your string from one end to the other.

If you just got your bow and it did not come with strings, there are a few basic strategies you can use to figure out how long your bowstrings should be. (1)

You have two options; the first is to measure the length of your bowstring personally, or you may use the AMO (Archery Manufacturers and Merchants Organization) length.

Don’t worry because we’ll go over both of these further below:

Method 1: Manually Measure the Bow String

For a longbow or recurve bow, measuring the bowstring length is simple. However, it is a lot more complicated with a compound bow. You will need the following items:

  1. Tape Measure
  2. Bow Press
  3. Permanent Marker
  4. Long Regular White String

You should measure from one outer pin on the cam, which you can find at the tip of the top riser, going through to the other outside pin on the cam at the bottom riser.

Step 1: Compress the Bow

This step will require you to perform two processes simultaneously. Since you can’t string and compress a bow at the same time, you’ll need help.

  1. Gather the equipment that you will need, and call a friend to help you out.
  2. Put the compound bow in a bow press with the risers facing you. If you don’t have a bow press, you can enlist the help of a friend to compress the bow.
  3. Put the bow upside down and ensure that it faces you by tightening the bow press vise grip. The cable slide should be vertical and in the center.

Step 2: Create a Loop

Form a loop on one end of the long piece of string. Remember to make a good knot to keep it in place.

Step 3: Place the Loop over the Pin

Place the loop over the pin on the upper riser’s cam facing towards you on your right. It is essential that you wind it properly.

Step 4: Pull the String towards the Other Cam

Pull the string towards the other cam while compressing the bow at the same time. Wind it by gently inserting it into the other cam on your right-hand side.

Step 5: Mark the String Using a Permanent Marker

Use a permanent marker to mark the end of the string with the length you want to buy. Next, loosen the string from the first cam, and then do the same thing with the other cam.

Step 6: Use the Tape Measure

Measure the length of the string from the loop to the spot where you marked it using a tape measure.

Method 2: Use the Bow AMO Length

Traditionally, you will see an AMO label in a bow, which pertains to the bow’s specified length. This is incredibly beneficial when measuring the length of the bowstring on a compound bow.

The AMO indicates the bow’s total length from tip to tip. The label on a compound bow will usually include statistics such as weight, string length, cable, and draw. In most situations, the bowstring length specified on the label is the one you will need for your bow.

So, if you have a compound bow with the specified AMO length visibly marked on it, you can use that to calculate the bowstring length of your bow. You will also see that the label includes the weight, string length, cable of the bow. It’s a lot easier than measuring by hand.

Take into account the string length for a compound bow weighing between 50 and 65 pounds is 58 inches. (2)

What’s the Best Way to Measure Your Bowstring’s Length?

I have presented to you two methods for determining the length of a compound bowstring. One way is to measure string length manually, and the other is to use the conventional AMO method. You may use both methods to determine the length of a compound bow string effectively. Here’s a more detailed guide on how to measure bow string.

The AMO Standard Method is the simplest way possible. However, there are circumstances that the AMO length label in your bow is missing. I highly recommend using the manual method since it also produces the most precise results.

Why is it Important to Properly Measure Your Bowstring Length?

Olympic archers spend lots of time attaching their bowstrings properly to acquire the best performance possible.

Therefore, if you want the best results, spend time and effort with your bow and adequately measure your bowstring length. You can do so using the AMO length and go through the quick process. 

However, there may be circumstances that the AMO labels are missing. In this case, it is best to measure your bowstring manually and follow the compound bow string guide here.

(1) strategies –
(2) pounds –