Skip to main content

Scales, Keys & Modes

Diatonic

Pronounced dye-uh-TON-ik

Definition

Diatonic describes notes, scales and chords that belong to a key's seven-note scale. A diatonic scale, such as the major scale, has five whole steps and two half steps in each octave.

Diatonic is an adjective with two closely related meanings.

  1. A diatonic scale is a seven-note scale made of five whole steps and two half steps, with the two half steps spread as far apart as they can be: two whole steps on one side of them, three on the other. The major scale, the natural minor scale and the seven church modes are diatonic scales. On the piano, the white keys form one.
  2. Diatonic notes and chords are the ones that belong to the key you are in. In C major, the diatonic notes are C D E F G A B. F♯ is not one of them, so in C major it is a chromatic note.
The seven diatonic notes of C major are the seven white keys. Any black key is a chromatic note in this key.

Diatonic chords

Build a triad on each degree of a major scale, using only the scale's notes, and you get the seven diatonic chords of the key. In C major they are C, Dm, Em, F, G, Am and B°. Their qualities come in the same order in every major key: major, minor, minor, major, major, minor, diminished. In Roman numerals that is I, ii, iii, IV, V, vi, vii°.

Treble clef in 4/4, four bars of half-note triads: C, D minor, E minor, F, G, A minor, B diminished and C. Chord symbols are printed above and Roman numerals I, ii, iii, IV, V, vi, vii diminished and I below.
A triad on each degree of C major, using only the white keys, with chord symbols above and Roman numerals below. Uppercase numerals are major chords, lowercase are minor, and vii° is diminished.

A chord that uses a note from outside the key, such as D major (with its F♯) in C major, is chromatic. Chromatic chords such as a secondary dominant or a borrowed chord add color, but in most tonal music the diatonic chords carry the bulk of the harmony. The chords of a key shows the pattern, and Name the chords of the key lets you practice it.

Diatonic and chromatic half steps

The word also sorts half steps. A diatonic half step moves to the neighboring letter name: E to F, or C♯ to D. A chromatic half step keeps the letter and changes the accidental: F to F♯, or B to B♭. On the piano they look and sound alike, but on paper they are different intervals: a minor second and an augmented unison.

Two treble-clef examples in 4/4 with half notes. Diatonic: E to F, then C-sharp to D. Chromatic: F to F-sharp, then B to B-flat.
Left: two diatonic half steps, E–F and C♯–D, each moving to a new letter. Right: two chromatic half steps, F–F♯ and B–B♭, each keeping its letter and changing the accidental.

Is the pentatonic scale diatonic?

Not in the strict sense. A diatonic scale has seven notes, and pentatonic scales have five. The five notes of a major pentatonic scale all belong to one diatonic scale, though, so a pentatonic melody sounds at home inside its key.

The opposite of diatonic is chromatic, and the chromatic scale, with all twelve notes, is the opposite of a diatonic scale.

Common questions

What does diatonic mean in music?

It means belonging to the key's scale. Diatonic notes and chords use only the seven notes of the key; chromatic ones add notes from outside it.

What is the opposite of diatonic?

Chromatic. A chromatic note, chord or scale includes notes outside the key's seven-note scale, such as F♯ in C major.

Practice it: free worksheets