Keys

What a key is

A free guitar lesson · 4 steps · about 7 minutes

Home

Hum the end of almost any song and you will land on a note that sounds finished, as if the music has come home. That home note is the key of the song. A song "in G" keeps coming back to G, and it feels like it should end there.

Knowing a song's key tells you which chords it is likely to use and which scale to solo with. This section shows you how.

The major scale

Every major key is built on a major scale: the do-re-mi you probably learned as a child. It has seven notes, and it is built from a fixed pattern of steps:

The major scale pattern: W is a whole step (2 frets), H is a half step (1 fret)

W  W  H  W  W  W  H

Start on any note and follow that pattern, and you get that note's major scale. Starting on C, with no sharps needed:

C major: C D E F G A B C

C --W-- D --W-- E -H- F --W-- G --W-- A --W-- B -H- C

The half steps fall exactly on E to F and B to C: the two places in the alphabet with no note between. That is why C major has no sharps or flats at all.

The C major scale on the guitar

C major, one octave, in open position

e|-------------------|
B|-------------0-1---|
G|---------0-2-------|
D|---0-2-3-----------|
A|-3-----------------|
E|-------------------|

Play it slowly and sing along: do, re, mi, fa, so, la, ti, do. That last C sounds like home, because it is.

Other keys need sharps

Start the same pattern on G and something has to give:

G major: G A B C D E F# G

G --W-- A --W-- B -H- C --W-- D --W-- E --W-- F# -H- G

To keep a whole step between E and the seventh note, F has to be raised to F#. So G major has one sharp. D major has two, A major three, E major four. The more sharps a key has, the further it is from C, and the circle of fifths at the end of this section shows the whole pattern at a glance.