Relative Major and Minor Keys
For every key signature there are two keys, one major and one minor. Keys which share a key signature are called relative keys. The minor scale used to determine key signatures for minor keys is always the natural minor scale.
For every major scale there is a relative minor scale which is based upon the 6th note (degree) of the major scale. This means that if you sing the C major scale starting and finishing on A (A B C D E F G A) instead of C, it becomes the A natural minor scale. Therefore, these two scales contain exactly the same notes. The only difference is that they start (and finish) on different notes. This chart shows the relative minor of all twelve major keys.
Both the major and the relative minor share the same key signature.
The sharpened 7th note that occurs in the relative minor key is never included as part of the key signature. Because each major and relative minor share the same key signature, you will need to know how to distinguish between the two keys. For example, a song with the key signature of F# thus
could indicate either the key of G major or its relative, E minor. The most accurate way of determining the key is to look through the melody for the sharpened 7th note of the E minor scale (D#). The presence of this note will indicate the minor key. If the 7th note is present, but not sharpened, then the key is more likely to be the relative major (i.e., D natural notes would suggest the key of G major).
Another method is to look at the first and last chords of the progression. These chords usually (but not always) indicate the key of the piece. If the piece starts and/or finishes with Em chords then the key is more likely to be E minor.
