Bow String Length Calculator
Using a bow string length calculator helps archers avoid the pitfalls of using an improperly sized string, to avoid poor performance or even damage to the bow.
How It Works
To use the bow string size calculator, you input the total bow length (in inches). The calculator then applies the formula:
$$ \text{BSL} = \text{BL} – 4 $$
where:
- BSL is the Bow String Length (in inches)
- BL is the total bow length (in inches)
For example, if the total bow length is 30 inches, the calculation would be:
$$ \text{BSL} = 30 – 4 = 26 \text{ inches} $$
This means the appropriate string length for a 30-inch bow would be 26 inches.
Bow String Length Calculation Formula
For most modern recurve and longbows, the general formula is:
Bow String Length = AMO Bow Length – 4 inches
Where AMO Bow Length refers to the standardized length measurement established by the Archery Manufacturers and Merchants Organization (AMO).
Related Tools:
What Length of Bow String Do I Need?
Determining the correct bow string length depends on several factors:
- Bow type: Recurve, longbow, or compound
- AMO bow length: The standardized measurement of your bow
- Brace height: The distance between the string and the deepest part of the bow grip when strung
To find the string length you need:
- Measure your bow’s AMO length
- Use the formula: String Length = AMO Length – 4 inches
- Create a string to this length and test it on your bow
- Adjust as necessary to achieve the desired brace height
How Long Should the String Be for a Longbow?
Longbows typically require a slightly different approach to string length calculation compared to recurve bows. The general rule of thumb for longbows is:
Longbow String Length = AMO Bow Length – 3 inches
This slight difference accounts for the unique characteristics of longbows, including their more traditional design and the way they bend when drawn.
How Long is a 62″ Bow String?
Using our standard calculation for a 62″ AMO bow length:
Bow String Length = 62″ – 4″ = 58″
A 62″ bow would typically require a 58″ string. However, this is a starting point, and minor adjustments may be necessary based on the specific bow and desired brace height.
What is the Length of a String for a 70-inch Bow?
Applying the same formula to a 70″ bow:
Bow String Length = 70″ – 4″ = 66″
A 70″ bow would typically use a 66″ string. Again, this is a starting point, and fine-tuning may be required for optimal performance.
Bow String Length Conversion Table
Here is a sample bow string length chart for various bow lengths using.
| AMO Bow Length (inches) | Calculated String Length (inches) | Notes |
|---|---|---|
| 58 | 54 | Typical for shorter recurve bows |
| 60 | 56 | Common length for many recurve bows |
| 62 | 58 | Standard length for many adult recurve bows |
| 64 | 60 | Longer recurve bow |
| 66 | 62 | Longer recurve or shorter longbow |
| 68 | 64 | Common length for tall archers or longbows |
| 70 | 66 | Long bow typically used in Olympic archery |
| 72 | 69 | Very long bow, often used for longbows |
