Intonation – an important yet nuanced thing that one should do while setting up their guitar.  Intonation is important because it places the entire guitar in tune rather than in just open position.  That is, it will be in tune no matter where you play.  Note, however, that intonation is just one step in a complete guitar setup.  Before intonating a guitar and in order for the intonation to work well, the neck must be bowed properly and the nut must be set correctly.  By intonating an electric guitar, one adjusts the length of each string by moving the bridge forward or backward.  For a guitar to be intonated, the 12^th fret must be perfectly under the middle of each string between the nut and the bridge.  You can tune a string to pitch, but intonation tunes a guitar to each string.

To start the intonation of your guitar you’ll need a very precise tuner and whatever tool is necessary for bridge adjustment for your particular guitar.  Different bridges can sometimes require different tools and can be adjusted from different angles.

Begin by:

1. Tuning all of the strings to pitch.
2. Then, play the 12^th fret harmonic of the low E string.
3. If the tuner says that the note is flat (too low), move the bridge saddle (which is the piece that the string rests over on the bridge) toward the neck of the guitar. This shortens the string length as well as the distance from the 12^th fret to the bridge.  If the harmonic note is sharp (too high), then adjust the bridge saddle away from the neck, thus lengthening the distance between the 12^th fret and the bridge.  Remember: flat forward, sharp back.  Always be sure to loosen the string before you adjust so you don’t damage your saddles. Once you make a small adjustment, tune back to pitch and check again.
4. Once adjusted, tune the open string to pitch and test if the 12^th fret harmonic is in tune. If it is, excellent!  If not, repeat the process and adjust accordingly.

Do this until both the open string and the 12^th fret harmonic are perfectly in tune.  Simply repeat these steps for all six strings and your guitar will be intonated!