How a capo actually works, explained with real math
A capo clamps every string at one fret, which raises the pitch of all open strings by one semitone per fret. That gives you one rule that explains everything:
The chord you hear = the shape you fret + the capo fret.
Fret a C shape with a capo on fret 2 and the room hears D. Fret an Am shape with a capo on fret 3 and the room hears Cm. The shape never changes; the capo does the transposing.
The table
Sounding chord for common open shapes at each capo fret:
| Shape | Capo 1 | Capo 2 | Capo 3 | Capo 4 | Capo 5 |
|---|---|---|---|---|---|
| C | C# | D | D# | E | F |
| G | G# | A | A# | B | C |
| D | D# | E | F | F# | G |
| Am | A#m | Bm | Cm | C#m | Dm |
| Em | Fm | F#m | Gm | G#m | Am |
Reading it backwards, the useful direction
Songbooks give you the sounding chords. What you actually want is the reverse: which easy shapes can produce those chords, and at which fret. That is a subtraction: shape = chord minus capo. If a song needs F, Bb and Cm, put the capo on fret 3 and the shapes become D, G and Am.
Doing that subtraction across a whole song, and only accepting frets where every chord lands on an open shape, is exactly what the PickMyPath engine does for each song in the catalog. On any song page here, if an all-open detour exists, it is shown with the exact fret.
Two honest caveats
- High capo positions (past fret 5 or so) start to sound thin and cramped. An available detour is not always the best-sounding one.
- A capo changes where shapes live, not how they feel. You still need clean open chords; the capo just lets you keep playing real songs while the harder shapes bake.
Let the app do the sequencing
PickMyPath is free and runs in the browser. Mark your chords, get your path.
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