Minor Scales & Keys

You’ll be able to

Construct the natural, harmonic, and melodic forms of a minor scale
Relate a minor key to its relative and parallel major
Determine a minor key signature from its relative major

The natural minor scale

A natural minor scale follows the step pattern W–H–W–W–H–W–W. Its darker color comes from three degrees that sit a half step lower than in major: the third, sixth, and seventh (♭3, ♭6, ♭7). A minor uses only white keys — A B C D E F G A — just as C major does, which is no coincidence: they are relatives, sharing the same seven pitches and the same key signature. The relative minor of any major key is built on that key’s sixth degree (la), a minor third below the major tonic (C major → A minor).

Harmonic and melodic minor

Natural minor has a weak ♭7 (subtonic) a whole step below the tonic, so it lacks a strong pull home. Two variants fix this. Harmonic minor raises the seventh degree by a half step, creating a true leading tone (ti) — but this opens an awkward augmented second between ♭6 and ♯7 (in A minor, F to G♯). Melodic minor smooths that gap by raising both the sixth and seventh degrees when ascending, then reverting to natural minor when descending. In A melodic minor: ascending A B C D E F♯ G♯ A, descending A G F E D C B A.

Relative vs. parallel; finding minor key signatures

Two keys can relate in two ways. Relative keys share a key signature but have different tonics (C major and A minor). Parallel keys share a tonic but different signatures (C major and C minor). To find a minor key signature, name its relative major by counting up a minor third (a minor third above A is C, so A minor takes C major’s signature — no sharps or flats). C minor’s relative major is E♭ major, so C minor carries three flats (B♭ E♭ A♭).

Relative and parallel relationships

relative major = up a minor third from minor tonic · parallel = same tonic, different mode

Relative keys share a signature (A minor ↔ C major). Parallel minor lowers the major scale’s 3rd, 6th, and 7th degrees (C major → C minor: E♭, A♭, B♭).

Worked example

Build the A harmonic minor scale and identify the interval that gives it its distinctive sound.

1.Start from A natural minor: A B C D E F G A.
2.Harmonic minor raises the seventh degree (subtonic) by a half step: G becomes G♯, producing a leading tone.
3.The scale is A B C D E F G♯ A.
4.Between the sixth degree F and the raised seventh G♯ lies three half steps written as a second — an augmented second, the exotic interval characteristic of harmonic minor.

Answer: A harmonic minor = A B C D E F G♯ A. Raising G to G♯ creates both a strong leading tone (G♯ → A) and an augmented second between F and G♯.

Checkpoint

What is the relative minor of C major?

Watch out

Harmonic and melodic minor are not new key signatures — the raised 6th and 7th are written as accidentals, not baked into the signature. A piece "in A minor" always carries the natural-minor signature (no sharps/flats); the G♯ of harmonic minor appears note by note as needed.

Checkpoint

E natural minor is spelled E F♯ G A B C D. Which alteration produces E harmonic minor?

On the exam

When you see a raised seventh degree used as an accidental in a minor-key passage, read it as harmonic minor supplying a leading tone for the V chord. That leading tone is what makes an authentic cadence possible in minor.

Answer the 2 checkpoints as you read.