How to measure bowstring length

How to Measure Compound and Recurve Bowstring In 5 Minutes

You might have felt the need to replace the bowstring because your string is worn or snapped. Now your first step is to find a replacement string but wait, what length string to buy? 

The choice of a string depends on not only the material but also on the length of the string. It is very easy to measure the string length by taking it off the bow and measuring from one end loop to the other end loop of the string.

But what if you don’t have a bowstring to measure? I will guide you with different easy methods to measure the bowstring length. The method is the same for recurve, long, and reflex deflex bows. Compound bows are a bit different.

Methods to Measure Bowstring Length

Let’s start by discussing the methods we will be using to measure the bowstring length. There are primarily two methods employed for this purpose: the manual method and the AMO (Archery Manufacturers and Merchants Organization) method.

Manual Method

The manual method is a straightforward approach that involves measuring the bowstring length by using a tape measure or a dedicated bowstring measuring tool. This method allows archers to determine the exact length of their bowstring by measuring it from grove to grove.

AMO Method

The AMO method is a standardized way of measuring bowstring length used by archery manufacturers and enthusiasts alike. It adheres to a set of guidelines established by the Archery Manufacturers and Merchants Organization, ensuring consistency and accuracy in string length measurement. This method measures the bow from grove to grove along the limb curvature to determine the AMO length. Then the AMO length is used to measure the bowstring length.

Both of these methods are essential for archers to select or create the right bowstring length for their specific bow.

How to Measure Recurve Bow String Length

Measuring the length of a recurve bow and its bowstring is a crucial aspect of proper archery setup. Here, I’ll explain two methods for measuring recurve bow length and string length, aimed at those who may not be familiar with the process:

Method 1: Measuring Manually

This method provides a straightforward way to measure the length of your recurve bow and its string.

Step 1: Start by safely unstringing your recurve bow, ensuring it is not under any tension.

Step 2: Measure the length of the bowstring by running the measuring tape or a string along the bowstring from one end loop to the other end loop. This measurement is your bowstring length.

Method 2: Using the AMO Standard

This method allows you to determine the AMO length of your recurve bow, which is a standardized measurement used in the archery community.

Step 1: Check for AMO Length Marking First

Check if your recurve bow has an AMO length marked on it. The AMO length is typically found on the bow’s limb. If you find this marking, that’s your AMO length.

Step 2: Measure Your AMO Length If your bow doesn’t have an AMO length marked, you can measure it yourself.

  1. Take a string and run it along the limbs of your recurve bow, following the curvature.
  2. Mark the string at the point where it lines up with the grooves where the bowstring rests when the bow is strung. Don’t follow the riser, follow the path of the limbs.
  3. Measure the marked string length.
  4. This is your AMO length.

Subtract 4 inches from this AMO length measurement to obtain your bowstring length.

demonstration of steps to measure amo length of recurve bow

For other bows like longbow follow the table recurve bow

Type of BowLength to subtract from AMO length
Long Bow3”
Reflex Deflex Bow3.5”
Recurve Bow4”

These methods will help you accurately determine the length of your recurve bow and its bowstring.

How to Measure Compound Bow String Length

Measuring the length of a compound bowstring is an important aspect of bow maintenance and setup. Here, I’ll explain how to measure a compound bowstring length using both the manual method and the AMO (Archery Manufacturers and Merchants Organization) method:

1. Manual Method

This method allows you to measure the bowstring length directly or by simulating a strung position.

Step 1 – Unstring the Bow: Begin by safely unstringing your compound bow to ensure there is no tension on the bowstring. Use a bow press to safely unstrung the bow.

Step 2 (Direct Measurement): Measure End Loop to End Loop – If possible, take a measuring tape and measure the distance from one end loop of the bowstring to the other end loop. This measurement represents your bowstring length.

Step 2 (Simulation Method): Use a String to Simulate the Bowstring – If you cannot directly measure the bowstring, take a string and create a loop on one end. Place this loop on one groove of the cam (the part that holds the bowstring). Follow the string along the cam tracks to the other cam, ensuring both cams are at the same position as if the bow were fully strung. Mark the string at this point.

Step 3 – Measure the String Length: After marking the string, remove it from the bow and measure the length between the two marks. This measurement is your bowstring length.

manual method to measure bowstring length

2. AMO Method

This method adheres to a standardized approach defined by AMO and requires measuring the arc length of the limbs.

Step 1: Locate the String Grooves – Identify the grooves on the limbs of your compound bow where the bowstring rests when the bow is strung.

Step 2: Measure the Limb Arc – Use a measuring tape or a flexible string to measure the arc length from one string groove on one limb to the corresponding string groove on the other limb. Ensure you go straight from the limb pocket without following the curvature of the riser.

Step 3: Calculate AMO Length – The measurement you obtained in Step 2 is the AMO length of your bow. If you want to convert this to compound bowstring length, you can use an AMO calculator, because it depends on various parts of the bow, so it is not that easy.

These methods will help you accurately determine the length of your compound bowstring, ensuring that you can select or adjust the appropriate bowstring for your bow’s specific requirements.

AMO length of compound bow

Which Method To Go For?

The choice between the manual method and the AMO method for measuring your compound bowstring length ultimately depends on your specific circumstances and preferences.

If Precision and Standardization Matter

If you value precision and want to adhere to industry-standard measurements, the AMO method is the way to go. It offers a standardized approach that is commonly recognized in the archery community. By measuring the arc length of the limbs, you ensure that your bowstring length aligns with widely accepted standards. This method is particularly important for competitive archers or those who require consistent measurements for their equipment.

If Simplicity and Convenience Are Key

On the other hand, if you prioritize simplicity and convenience, the manual method, especially the direct measurement, might be your preferred choice. It doesn’t require as much equipment or calculations. Simply measure from one end loop to the other if possible, or use the simulation method with a string and marks if direct measurement is not feasible. This approach is suitable for recreational archers or those who don’t require strict adherence to AMO standards.

How Long Should Compound Bow String Be?

For the best performance and safety, adhere to the manufacturer’s specifications and AMO standards when determining your compound bowstring length. This ensures proper functionality and compatibility with your bow’s design.

Why Precisely Measure Compound Bow String Length?

Perfectly measuring the compound bow string length is critical for several compelling reasons.

Accuracy: Accurate string length ensures consistent arrow flight and precise aim. It’s like having a calibrated instrument for each shot, increasing your chances of hitting the target.

Performance: An incorrectly measured string can have inappropriate tension. This can lead to string snapping or bow failure.

Safety: An improperly measured string can place excessive stress on the bow’s limbs, potentially leading to equipment failure or even personal injury. Perfect measurement helps maintain your safety.

Consistency: Archery success relies on consistency. A precise string length contributes to shot-to-shot uniformity, enabling you to fine-tune your skills and improve overall performance.


How is bow string length measured?

Bow string length is measured from one end loop to the other while the string is unstrung. There are other manual and AMO methods for different types of bows

What size string for a 60-inch bow?

For a 60-inch bow, you typically use a string that’s a few inches shorter, depending on the bow’s specifics. 

Is bow length measured strung?

Bow length is usually measured unstrung from tip to tip along the curvature of the limbs or by measuring the bowstring from end to end.


You now know how to measure the right string length for you. All you got to do is buy a new string of that size and carefully restring the compound bow. Make sure to look out for safety as the bowstring has a lot of tension stored and it can hurt you badly. Follow the steps to get the correct measurement of your bowstring.

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