Bow String Length Calculator

Bow Type:

Bow Length (AMO):

Desired Brace Height:

String Material:

Number of Strands:

Serving Type:

Recommended String Length:

Acceptable Range:

AMO String Length:

Actual Brace Height:

Estimated String Weight:

Tuning Notes:

Getting the correct bow string length is essential for accurate shooting, safety, and bow performance. A string that is too short can over-stress your limbs, while a string that’s too long can reduce draw weight, accuracy, and arrow speed.

The Bow String Length Calculator eliminates the guesswork by helping you find the ideal string length based on your bow’s type and AMO (Archery Manufacturers Organization) specifications.

Whether you shoot recurve, longbow, or compound, this tool ensures your bow is always tuned for optimal performance and consistency.

What Is a Bow String Length Calculator?

A Bow String Length Calculator is an online tool that quickly determines the correct string length for a bow using basic measurements such as:

AMO bow length
Bow type (recurve, longbow, or compound)
Desired brace height and string material stretch

It applies the standard AMO guidelines which state:

For recurve bows, string length ≈ AMO length − 3″
For longbows, string length ≈ AMO length − 4″
For compound bows, manufacturer specs are usually used directly

This makes the calculator a fast, accurate, and reliable method for archers to set up or replace their bow strings.

Why Correct Bow String Length Matters

Using the right string length is crucial for:

🎯 Accuracy: Consistent brace height improves arrow flight.
⚡ Performance: Maintains the intended draw weight and energy transfer.
🛡️ Safety: Prevents limb damage from over-stressing the bow.
💪 Durability: Reduces wear on the string, cams, and limbs.

A wrong string can make your bow hard to draw, loud, inaccurate, and even dangerous.

How to Use the Bow String Length Calculator

Using this calculator is simple and only takes a few minutes. Follow these steps:

Step 1 — Identify Your Bow Type

Determine if your bow is a recurve, longbow, or compound.
This matters because each type uses a different string length ratio.

Step 2 — Find Your AMO Bow Length

Check your bow limb for the AMO length marking (usually in inches).
If not listed, measure the unstrung bow from tip to tip along the curve.

Step 3 — Enter Your Measurements

Enter your AMO length and select your bow type in the calculator.

Step 4 — Calculate

Click the “Calculate” button.
The calculator applies the AMO formula and gives you the recommended string length.

Step 5 — Apply Adjustments (Optional)

If using high-stretch materials (Dacron) or low-stretch (Fast Flight), adjust slightly:
- Dacron may stretch → go slightly shorter
- Fast Flight doesn’t stretch → exact length is fine

Practical Example

Given:

Bow Type: Recurve
AMO Length: 68 inches

Calculation:

String Length = AMO Length − 3"
String Length = 68 − 3
String Length = 65"

✅ Result: You need a 65-inch bow string for your 68-inch recurve bow.

Features of the Bow String Length Calculator

✅ Works for recurve, longbow, and compound bows
✅ Uses AMO standard calculations
✅ Supports inches or centimeters
✅ Instant results in seconds
✅ Mobile-friendly interface
✅ Reset and recalculate for multiple bows

Benefits of Using This Tool

🎯 Accuracy: Ensures proper brace height and performance
💸 Cost Savings: Avoid buying incorrect string sizes
⏱️ Time-Saving: No manual calculations needed
🛡️ Safety: Prevents limb stress or string slap injuries
💪 Consistency: Improves shooting form and accuracy

Common Use Cases

🏹 Replacing an old or worn-out bow string
🧩 Tuning a new bow for accurate brace height
⚙️ Building a custom recurve or longbow
🧪 Experimenting with different string materials
🎯 Setting up bows for archery clubs or teams

Helpful Tips for Accurate Results

Always measure AMO length on an unstrung bow.
Double-check your bow type, as recurve and longbow formulas differ.
Add string silencers only after setting brace height.
If unsure between two sizes, choose slightly shorter (you can twist to adjust).
Recheck brace height after installing your new string, as it may stretch initially.

FAQ — Bow String Length Calculator

Here are 20 common questions and answers about using this tool:

1. What does this calculator do?

It calculates the correct bow string length based on your AMO bow length and type.

2. What is AMO length?

It’s the industry standard unstrung bow length used for sizing strings.

3. How do I find my AMO length?

Check your bow limb markings or measure tip-to-tip along the curve.

4. Does bow type matter?

Yes, recurve and longbow strings differ by about 1 inch per AMO formula.

5. What is the recurve formula?

String length ≈ AMO length − 3″.

6. What is the longbow formula?

String length ≈ AMO length − 4″.

7. How about compound bows?

They use manufacturer specs, so enter the recommended string length directly.

8. What if I don’t know my bow type?

Check limb shape: recurves have pronounced curves; longbows are straighter.

9. What is brace height?

It’s the distance from the bow grip to the string when strung.

10. Does string material matter?

Yes, high-stretch strings (Dacron) may need slightly shorter lengths.

11. Can I use this for crossbows?

No, this is only for traditional, recurve, and compound bows.

12. Should I round up or down?

If in doubt, round down slightly—you can add twists to shorten.

13. What if my bow has no markings?

Measure its unstrung length along the curve.

14. Can I enter metric units?

Yes, just use the same unit consistently.

15. Does string thickness affect length?

No, thickness affects weight and speed, not length.

16. Can I use an old string to measure?

Yes, if it’s not stretched or worn out.

17. Do I need to measure with the bow strung?

No, always measure AMO length on an unstrung bow.

18. Can this help me build custom strings?

Yes, it gives a precise starting length for building strings.

19. Will this improve my accuracy?

Yes, correct string length ensures ideal brace height for accuracy.

20. Is this tool free?

Yes, it’s completely free to use.

Final Thoughts

The Bow String Length Calculator is a must-have tool for any archer. It removes the guesswork from choosing the right string, ensuring your bow is safe, accurate, and efficient every time you shoot.

Whether you’re setting up a new recurve, maintaining a longbow, or tuning a compound, this calculator gives you fast and reliable results so you can spend less time measuring and more time shooting.