On a guitar, what keys correspond to different capo positions?

Question

I've long had this question. I know some music theory, but I can only get a vague idea as to the progression of keys when moving the capo down a guitar's neck. I'm fairly certain that the guitar is in the key of E minor when no capo is used, but that may be wrong. When playing some songs, the instructions for capo position aren't something like "Capo on fret 3", but, instead, "Capo: C Major" or "Key: C Major". I've tried to find a description of this online, but the closest things that I've been able to find are descriptions of how to transpose chords to different keys. Any help is appreciated, and I wouldn't be surprised if I had some gross conceptual error.

Answer 1

Good question but a loaded one!

What I always tell my students is you must be "bilingual" with the capo. What is it in guitar and then what is it in the real key.

e.g.

Capo on the 2nd fret and play a G. In guitar talk it is a G, but it really is an A.

Capo 4th fret and play a C. In guitar talk it is a C, but it really is an E.

Capo 5th fret and play a D. In guitar talk it is a D, but it really is an A.

etc.

Have fun!

Answer 2

The key of the music isn't determined by where you place the capo. For example, with no capo it's still very easy to play in the keys A, C, D, G, E, along with Em, Dm, and Am.

The low E doesn't influence the key of the music at all. However, it does provide a nice drone note, which influences how you hear the key you're playing in.

So let's say you place the capo on the 5th fret. If you play what would normally be the key of E or Em, you are instead playing A or Am. However, if you play what would normally be in the key of A or Am, you're actually playing in the key of D or Dm, due to omitting the low E string as the tonal center and instead passing that role off to the A string.

Saying something like "capo: c major" is an error. Any key can be played with the capo in any location provide you have enough frets left for the notes of that particular scale.

So this isn't really so cut and dry. What it really boils down to is; it depends.