A capo is more than just a “cheater” (something that is used to avoid playing barre chords) – it’s a valuable tool that will allow you to use the chord voicings of your choice, as well as play more easily in some of the non-guitaristic keys that other instruments favor or your vocal range prefers.

Even experienced guitar players can get confused about keys when they use a capo, and the confusion is magnified when they begin communicating with other musicians. The first step toward clarity is to learn how to tell the key you are actually playing in, capo or not. In order to determine the key of a song, you can look at the chord progression, starting with the most common progression: I, IV, V. For example, if a song has G, C and D chords, it is in the key of G, G being the I chord, C being the IV and D being the V. If you’re not sure about which chords are the I, IV and V in a key, refer to the major scales. It is also helpful to remember that most songs will end on the tonic chord (the one that is the key name).

Once you are sure of the key, simply go up the order of notes ½ step for each fret you move the capo up the guitar neck. (This is the same way that you find notes on the fretboard.) For instance, if you are playing a shape that you normally use for a G chord and you put the capo on the 1st fret (capo I), you will be playing a G♯ or A♭. When you move the capo to the 2nd  fret (capo II), the chord becomes an A. Likewise, if the song is played with the chord shapes of G’s, C’s and D’s, but you have the capo on the second fret, you are actually playing in the key of A. Put the capo on the 3rd fret and you will be playing in the key of B♭ (even though the chords may not look like that to you!).

How to Handle Soloing
When playing melodies or soloing, forget that the capo is on! The 8th fret on the 1st string is a C, whether there is a capo behind it or not. Your scale patterns will still work, provided you stick to the ones that you can play high enough on the neck to be in front of the capo. So, know what key you’re in, forget that the capo is there, and use your scale patterns to solo the way you normally would.

Practice

Now it’s time to practice what you’ve learned. (Answers follow)

In all of the instances on the next page, determine where you will place the capo in order to play in the new key while using the chord shapes from the original key.
 
1.     The song is in the key of G and you want to play it in B♭

2.     The song is in the key of Am and you want to play it in Fm

3.     The song is in the key of C and you want to play it in E

4.     The song is in the key of D and you want to play it in G♭

5.     The song is in the key of Dm and you want to play it in Em

6.     The song is in the key of A and you want to play it in E♭

 
Answers: 1. capo III  2. capo VIII  3. capo IV  4. capo IV  5. capo II  6. capo VI

Now let’s turn it around and start with a key, then determine what shapes you could use and where you would put the capo.

  1. You want to use common, first position chords to play in the key of F
  2. You want to use common, first position chords to play in the key of C♯
  3. You want to use common, first position chords to play in the key of B

 Answers: 1. E, capo I; D, capo III; C, capo V; A, capo VIII   2. C, capo I; A, capo IV; G, capo VI  3. A, capo II; G, capo IV; E, capo VII