A capo lets you play songs in any key with the open chord shapes you already know. Put it on the 3rd fret and your G, C and D shapes sound as Bb, Eb and F. The hard part is knowing where to put it, and this calculator does that for you.
Choose the key you want to sound in (the one that suits your voice or the original recording), or type the song’s chords as they appear on a chord sheet. The calculator tries every capo position from none to the 9th fret, works out which shapes you would play at each one, and rates every shape by how hard it is near the nut: open chords like G, C, D, Em and Am score best, barre chords like F, Bm and Bb count against. The easiest positions come first.
Each position shows the shape you play and the chord it sounds right next to each other, so you can read a chord sheet and play from the shapes at the same time. Tap a position to see the chord diagrams for its shapes and press Play to hear the progression with the capo on.
Already have a capo on? Switch to “What my capo does”, choose the fret, and type the shapes you play to find out which chords and which key you are really in, for example to tell a bass player or a singer.