To understand how capos work, it first helps to understand the parts of the guitar and how those work.
How pitch is determined
The string lays across the saddle a the bridge, and then it passes over the nut near the headstock. Those (and the frets, when you fret a sting) determine the length of the string. The string’s length, tension, and thickness determines the not that the string plays. As you shorten the string, the pitch goes higher. As you move up the fretboard, each fret causes the string to ring one half-step higher.
What a capo does and how it changes pitch
The capo is typically a device with a long arm that lays across all the strings and some kind of way to hold tension so that it frets all the strings on whatever fret you put it on. Essentially, it moves the nut up the fretboard, causing all the strings to ring higher in pitch as you move the capo higher on the fretboard.
How chords change with a capo
This works with both strings and chords. If you play an E chord without a capo, it’s an E. If you play that same E with a capo on the 1st fret, it’s one half-step higher, so now it’s an F. Capo on the 2nd fret and it’s an F#. Keep going and it works out like this:
Playing an E chord:
- Capo off: E
- Capo on 1st fret: F
- Capo on 2nd fret: F# (or Gb)
- Capo on 3rd fret: G
- Capo on 4th fret: G# (or Ab)
- Capo on 5th fret: A
- Capo on 6th fret: Bb (or A#)
- Capo on 7th fret: B
You can see that with each fret, the chord goes up one half-step. This works for any chord you play.
Check out the rest of the lessons in the Capos series to learn more.