How a capo works
A capo clamps across the neck and acts as a movable nut. Each fret you move it up raises all six strings by one semitone, so every chord you play sounds higher while the shape under your fingers stays the same. An E shape with the capo on fret 1 sounds as F, on fret 2 as F#, and on fret 3 as G.
That gives you two practical benefits. You can play in awkward keys, such as Bb or F#, using familiar open shapes, and you can change a song key to suit your voice without learning new fingerings. A capo also keeps open strings ringing in keys where you would otherwise need barre chords, which changes the character of the sound.
Finding the capo fret for a key
Pick the key you want to sound in and the key of the shapes you want to play. Count semitones upward from the shape key to the target key, and that is the capo fret. G shapes to reach Bb is three semitones, so fret 3. C shapes to reach E is four semitones, so fret 4. If the answer is zero, no capo is needed. If it is more than about seven, try a different shape key with a lower fret.
Handy examples
- Play in Bb using G shapes (capo 3), or A shapes (capo 1).
- Play in F using D shapes (capo 3), or C shapes (capo 5).
- Play in F# using D shapes (capo 4), or E shapes (capo 2).
- Play in Eb using C shapes (capo 3), or D shapes (capo 1).
- Play in B minor using Am shapes (capo 2), or Em shapes (capo 7).
Sharps, flats and chord names
The same note can have two names: C# and Db, or A# and Bb. Which one is correct depends on the key, but both name the same pitch, so a capo calculator works the same either way. Use the Sharps, Flats or Auto buttons to choose how results are written. Chord qualities such as minor (m), 7, maj7, m7, sus2, sus4, add9, dim and aug are carried across unchanged, and the bass note of a slash chord moves along with the root.
Capo and guitar tone
Moving a capo up shortens the vibrating string length, which brightens the tone and tightens the low end. That is useful when you want a jangly acoustic feel, but on an electric guitar through a distorted amp it can sound thin, since the amp settings that suit full-length strings are no longer ideal. If you are chasing a recorded tone, remember the original player may have used a capo too. To find the amp settings behind a song, browse amp settings for songs, or use ToneAdapt to adapt them to your gear. For pedal setups see the pedal order guide, and keep time with the online metronome.
Frequently asked questions
How does a capo change the key?
A capo raises every open string by one semitone per fret. Playing a G shape with the capo on fret 2 sounds as A, and every other chord in the progression moves up by the same amount. The shapes stay the same under your fingers while the pitch rises.
How do I work out which capo fret to use?
Count the semitones from the key of the shapes you want to play up to the key you want to sound in. To play in Bb using G shapes, G to Bb is three semitones, so the capo goes on fret 3. The calculator above does that for you, for any key.
What capo position should I use to sing a song in my range?
Work out the song key that suits your voice, then choose the easiest open shapes (usually G, C, D, A, E or their minors) that reach it with the capo on a low fret. Frets 1 to 5 are the most comfortable and keep the guitar sounding full.
What is the highest useful capo fret?
Most players stay at or below fret 7. Higher up the guitar gets thin and bright, and the frets become cramped. If you need to go past fret 7, consider using shapes from a different key that need a lower capo.
Do slash chords and extended chords work with a capo?
Yes. A slash chord such as D/F# has both a chord and a bass note that move up by the same number of semitones. Extensions and qualities like m7, maj7, sus4, add9, dim and aug stay the same and only the root changes.