Guitar and technique
Capo
A capo is a clamp that presses all the strings at one fret; it acts as a new nut and raises everything you play by one semitone per fret.
What does a capo do on a guitar?
A capo clamps across the neck and holds all six strings down at a single fret. It becomes a movable nut: your open chords keep the same fingering, but everything sounds one semitone higher per fret.
So you keep the sound of open strings (ringing bass notes, shimmering trebles) in any key, without switching to barre chords. It is the simplest way to fit a song to a singer's voice.
How do you work out the key with a capo?
The rule: shape you play + capo fret = chord you hear. With the capo at the 2nd fret, a G shape sounds as A, because G plus two semitones is A.
| Capo | G shape | C shape | D shape | E shape |
|---|---|---|---|---|
| 1 | Ab | Db | Eb | F |
| 2 | A | D | E | F# |
| 3 | Bb | Eb | F | G |
| 4 | B | E | F# | Ab |
| 5 | C | F | G | A |
| 7 | D | G | A | B |
A concrete example: G, D, Em, C played with a capo at the 2nd fret sounds as A, E, F#m, D.
Which fret should you put the capo on?
Work backwards: key you want minus key of your shapes.
- Song in Bb, you want to play G shapes: G to Bb is 3 semitones, so capo 3.
- Song in E, using C shapes: C to E is 4 semitones, so capo 4.
- Song in F, using D shapes: capo 3.
Above the 7th fret the sound gets thin and the frets cramped, so pick other shapes with a lower capo instead. To keep track, the songbook transposes your chord sheet and lets you note the capo fret.
Exercise: one progression in three keys
Play the pop progression I-V-vi-IV with G shapes (G, D, Em, C), one bar per chord:
- No capo: you are in G.
- Capo at the 2nd fret: you are in A (A, E, F#m, D).
- Capo at the 4th fret: you are in B (B, F#, G#m, E).
Sing the melody each time and note which fret suits your voice. Two-guitar version: one player uses D shapes with no capo (D, A, Bm, G), the other C shapes with capo 2 (C, G, Am, F). Both sound in D, but the voicings differ and the blend is much richer.
Common capo mistakes
- Capo in the middle of the fret space: set it right behind the fret wire, or strings buzz and go sharp.
- Too much tension: it pulls the strings sharp. Retune after clamping, even in standard tuning.
- Calling chords by their shapes: with a bass player, call the real chords (A, E), not the shapes (G, D).
Key takeaways
- Each capo fret raises everything by one semitone.
- Shape plus capo fret equals the sounding chord: capo 2 with G shapes sounds in A.
- To choose the fret, count the semitones from your shape's key to the target key.
- Clamp right behind the fret wire and retune.
Frequently asked questions
Is using a capo cheating?
No. Many professional players use one to keep open strings in keys like Bb or Eb. It changes the colour of the sound, not just the difficulty: a G shape with capo 3 rings brighter than a barred Bb chord.
Can you use a capo in an open tuning?
Yes. In Open G, Open D or DADGAD the capo raises the whole tuning: Open G with a capo at the 2nd fret becomes Open A. Your fingerings stay exactly the same.
Does a capo damage the guitar?
Not if it is set correctly. Take it off when you stop playing, especially a strong spring model, and avoid leaving it on the neck for days, since it keeps pressing on the frets and fingerboard.
Related terms
Practise in the workshop
Take it from theory to the fretboard
Open the workshop tools and see this idea across the whole neck. Free account, no card needed.