Capo chart
A capo moves the open strings up, so the shapes you already know sound in a new key. Pick the key you want to hear and the chart lists where to put the capo and which shape to play there.
Each fret is one semitone. A capo on fret 1 makes an open C shape sound as C#, fret 2 makes it D, fret 3 makes it D#, and so on to fret 7, which sounds that shape as G. The same rule runs backwards: an A shape under a capo on fret 3 comes out as C.
Guitar shapes wrap, and that is what makes a capo a choice rather than a trick. To hear C you can play an open C shape with no capo, a G shape with the capo on fret 5, or a D shape with the capo on fret 2 and a bar chord. One key has several positions, and the one you want depends on which shapes you can finger cleanly and where the song sits for the singer.
Two things go wrong with a capo and both are tuning problems, not chart problems. Press it too hard and the outer strings bend sharp, which a tuner checked at the 12th fret will show you, so tune after fitting it rather than before. On a slim-necked guitar a low capo crowds the fretboard and the shapes get cramped; move it up a fret and change the shape.
The chart runs from open position to the seventh fret, which is where a capo stops being useful: past that the neck gets tight and the shapes thin out. Every key in 12-tone equal temperament follows from one rule, capo fret plus the open-key name of the shape, in either direction.
SUS4 Capo Calc
SUS4 Capo Calc goes the other way round: name the key you want to hear and it lists every capo position to the seventh fret with the shape to play there, easiest first, each with a chord diagram. It follows your tuning across 25 options, standard, dropped, open and modal. Free to download; Pro is £0.99 a month after a 7-day trial.
The app version keeps your settings and works with no internet: on a stage, in a rehearsal room, or on a train. It runs on iPhone, iPad, Mac and Apple Watch.
Other free tools
- Online guitar tunerA chromatic tuner in your browser. Play a note and see the pitch, the nearest note and how many cents sharp or flat you are. Guitar, bass, ukulele and violin.
- BPM counterTap along to a song and get its BPM in the browser. Shows the tempo, the subdivision you are tapping and how long a bar lasts, with the standard tempo words.
- Note to frequencyLook up any note in hertz, or any frequency as a note. A4 is 440 Hz; the table runs from C0 at 16.35 Hz to C8 at 4186 Hz, each with its cents offset.
Guides, apps and plugins
- SUS4 Chord IDPlay a chord into the mic and get its name.
- SUS4 Scale Lab104 scales and modes lit up on the fretboard and on piano keys.
- SUS4 CrimsonAn overdrive built for guitar, once the key is right.