Archery String Length Calculator

The correct string length sets your bow’s brace height, the distance from the grip to the string at rest.
Get the string length wrong and the brace height is wrong, which costs performance and, at the extremes, is a safety problem.

AMO (Archery Manufacturers Organization) convention: AMO bow length is measured along the back of the bow from tip to tip.

The formula:

String length = AMO bow length − offset

A recurve takes the larger offset because its curved tips eat more of the bow’s measured length than a longbow’s straight limbs do. The three offsets above are exactly what the dropdown applies, so the table and the calculator cannot drift apart.

Brace height by bow type:

• Recurve (competition, 66–70 in): 8.5–9.5 inches brace height
• Recurve (hunting, 58–64 in): 7.0–8.5 inches brace height
• Longbow: 6–7 inches (varies by design)
• Traditional/selfbow: 5–6 inches

Effect of string length on brace height:

• Shorter string = higher brace height = more forgiving, slower
• Longer string = lower brace height = less forgiving, faster

Twist adjustment: Recurve strings can be twisted to fine-tune brace height. Adding twists shortens the string slightly, raising brace height. Untwisting lowers brace height. Standard starting twists: 12–16 for a 62-inch string.

Compound bow strings: Compound bows use a different measurement system entirely.
Always replace compound strings with the factory-specified length. A string even slightly off changes draw weight and throws cam timing out, and neither is something you can twist back into place.