Intonation refers to how accurately a guitar stays in tune across the entire fretboard. Even if the open strings are perfectly tuned, poor intonation can cause notes—especially past the 8th fret—to sound sharp or flat. This guide explains how to check and adjust intonation, primarily for electric guitars with adjustable bridges.
What Is Intonation?
Intonation ensures that fretted notes match the pitch of their corresponding open strings. If the 12th fret note is not in tune with the open string, the guitar’s intonation is off. This affects how chords and melodies sound, especially in higher registers.
Acoustic vs. Electric Guitars
🎸 Electric Guitars
- Most electric guitars have adjustable bridge saddles, allowing precise intonation adjustments.
- Common bridge types include Tune-O-Matic, Strat-style, and Floyd Rose.
🎻 Acoustic Guitars
- Standard acoustic guitars do not have adjustable saddles.
- Intonation issues may require saddle reshaping or repositioning by a technician.
How to Check and Adjust Intonation (Electric Guitars)
Step-by-Step Instructions
-
Tune the Guitar
- Use a reliable tuner to tune each string to your desired pitch.
-
Check the 12th Fret
- Play the string open.
- Then press and play the 12th fret.
- Compare both pitches using your tuner.
-
Evaluate the Pitch
- If the 12th fret note is sharp (higher than the open string):
- Turn the saddle screw to lengthen the string (move saddle away from the nut).
- If the 12th fret note is flat (lower than the open string):
- Turn the saddle screw to shorten the string (move saddle toward the nut).
- If the 12th fret note is sharp (higher than the open string):
-
Repeat and Fine-Tune
- Re-tune the string after each adjustment.
- Re-check the 12th fret pitch.
- Repeat until both open and fretted notes match.
-
Apply to All Strings
- Repeat the process for each string individually.
Tips for Safe Adjustment
- Make small changes—¼ turn at a time.
- Always re-tune after each adjustment.
- Let the guitar settle for a few minutes before rechecking.
- Use the correct screwdriver or Allen wrench for your bridge type.
Conclusion
Proper intonation ensures your guitar sounds in tune across the entire neck. While electric guitars allow for direct adjustments via the bridge, acoustic guitars may require professional help. Regular intonation checks are essential for maintaining optimal playability and tone.