Chords for your melody

Write a melody and hear it with chords that fit, by the rules of harmony.

Your song

Plain letters are the octave from middle C up: C D E. Add + for the octave above (C+) and - for the octave below (G-). Each note is one beat; a dash after it holds one more beat (C -). Two notes in one beat: B.G. Shorter notes: A/2, A/4, A/8. | between measures is optional.

Put the words on the line under their notes, one syllable for each note. Join the parts of a word with a hyphen (ho-ly); _ leaves a note without a word, and y_en puts two words on one note.

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Note names

Key

Beats in a measure

Chords to use

Change chords
Sevenths Smooth bass

Choose a way

Take the chords along

Each button opens another free page in a new tab, with these chords already filled in. This page stays open.

The theory, step by step

How the page chooses, in six short lessons. You can use the same steps with pencil and paper.

1Every note fits three chords

A chord is three notes stacked in thirds, so every note of the scale belongs to three chords: as their root, their third or their fifth. In C major the note E is in C (C E G), in Em (E G B) and in Am (A C E). That is where the choices under each note come from.

  • Note 1 fits I, IV and vi.
  • Note 2 fits ii, V and vii°.
  • Note 3 fits I, iii and vi.
  • Note 4 fits ii, IV and vii°.
  • Note 5 fits I, iii and V.
  • Note 6 fits ii, IV and vi.
  • Note 7 fits iii, V and vii°.
2Where chords like to go

Chords lean toward home in a set order: iii, then vi, then IV or ii, then V or vii°, then I. A step forward on this road sounds natural: vi to ii, ii to V, V to I. The home chord can go anywhere. A step backward, like V to IV, weakens the pull.

Some moves are rare: ii does not go straight to I, and iii and vi do not go straight to V. IV to ii is common, ii to IV less so. In minor the road is VII, III, VI, iv or ii°, V or vii°, i. The V of a minor key is major, because the seventh note is raised: E, not Em, in A minor.

3How phrases end

A phrase is a musical sentence, often four measures long, and its last two chords are its cadence.

  • Perfect authentic cadence: V to I, both with their root in the bass, the melody ending on 1. The full stop.
  • Imperfect authentic cadence: V to I with the melody on 3 or 5, or with a chord inverted. It ends, a little softer.
  • Half cadence: the phrase stops on V. A comma: the music asks to go on.
  • Plagal cadence: IV to I, the “Amen” of hymns.
  • Deceptive cadence: V to vi. A surprise that keeps the song going.

Many songs answer a phrase that stops on V with one that comes home on I. The very last cadence is V to I, never vii° to I.

4How often to change chord

The speed of the chord changes is the harmonic rhythm. Changes fall on strong beats, often once a measure, and tend to come faster near the end of a phrase.

Melody notes between the changes do not need a chord of their own. A note that steps between two chord notes is a passing note and can belong to no chord at all. That is why the page looks first at the note on each change.

5A smoother bass

A chord can stand on its third instead of its root. C/E is C with E in the bass, called first inversion and written I6. Inversions let the bass move by step instead of leaping, and make a chord lighter inside a phrase.

Keep the last V and I on their roots; that is what makes the ending strong. A diminished chord (vii°) sounds best in first inversion, so the page always writes it that way.

6Sevenths

Adding the seventh note above the root makes a chord lean forward. V7 pulls home harder than V, so it suits the last cadence, and ii7 leads well into V. A phrase that stops on V keeps it plain, and the home chord at the end stays plain too.

Strum Tempobpm Beat tick

Your melody and chords

Key: C major · 4/4 · Measures: 8. Phrases: 2. Chord changes: 8.

Notes on your choices

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