Guitar Intonation Guide: Why Your Guitar Goes Out of Tune Up the Neck

Intonation is one of the most misunderstood concepts in guitar maintenance — yet it directly affects how musical your instrument sounds, especially in a band context.

What Is Intonation?

Intonation describes how accurately your guitar plays in tune across the entire fretboard. A guitar with perfect intonation plays the same pitch at the open string, the 12th fret harmonic, and the 12th fret fretted note.

If the fretted 12th is sharp compared to the harmonic, the string is too short — the saddle needs to move back. If the fretted 12th is flat, the string is too long — the saddle needs to move forward.

Common Causes of Intonation Problems

String gauge change: Switching from 9s to 10s changes string tension and requires intonation adjustment.

String age: Old strings develop intonation issues because uneven wear changes the string's vibrating mass.

Temperature and humidity: Wood expands and contracts, shifting neck relief and string height.

Capo pressure: Excessive capo tension pulls notes sharp. This is a primary reason to use an adjustable tension capo.

How to Check Intonation

1. Tune the open string to pitch (use a chromatic tuner) 2. Play the 12th fret harmonic — it should match exactly 3. Press the 12th fret and compare to the harmonic 4. Adjust the saddle if they differ by more than 2 cents

Professional Setup Recommendation

For electric guitars with adjustable saddles, intonation can often be set at home. Acoustic guitars typically require a luthier to adjust the saddle. Ask our Pro Concierge to connect you with a resource.

Preventing Intonation Drift

- Change strings regularly (PGL Performance Series) - Use an adjustable tension capo - Store your guitar in a temperature-stable environment