Topmusicanswers
By "Tuned to C major" what you mean is, it's analogous to a transposing woodwind/brass instrument "in C", in that C major chord shape will produce concert C major. Capo at 4th fret now makes your guitar "in E".
What key is capo on 4th fret?
Transpose with help of the capo
| Capo 2 | D | Em |
| Capo 3 | D#/Eb | Fm |
| Capo 4 | E | F#m/Gbm |
| Capo 5 | F | Gm |
| Capo 6 | F#/Gb | G#m/Abm |
What chord is on the 4th fret?
The capo on the fourth fret moves the pitch up four half steps. From our original G chord, that would be G#/Ab, A, Bb, B. Our G, C and D chords now sound like B, E and F#. This C chord with the capo on the fourth fret sounds like an E chord.
What key am I playing in with a capo?
If you play with a capo on the 2nd fret a song with chords like G, C and D will sound like A major. If you play with a capo on the 4th fret a song with chords like C, F and G will sound like E major.
