In music, a pentatonic scale is a scale with five notes per octave. Pentatonic scales are found all over the world: in the tuning of the Ethiopian krar and the Indonesian gamelan, in the melodies of African-American spirituals and of composer Claude-Achille Debussy.

One of the most common pentatonic scales, sometimes called a major pentatonic scale, can be constructed in many ways. A simple construction takes five consecutive pitches from the circle of fifths: if starting on C, {C, G, D, A, E}. This leads to a Pythagorean scale of {1/1, 9/8, 81/64, 3/2, 27/16}. A more complicated construction, derived from Western European classical music, begins with a major scale and omits the fourth and the seventh scale degrees: a C major scale is {C, D, E, F, G, A, B}, so a C major pentatonic scale would be {C, D, E, G, A} which leads to a just scale of either {1/1, 9/8, 5/4, 3/2, 5/3} (a 5-limit pentatonic) or {1/1, 9/8, 21/16, 3/2, 7/4} with blue notes of the flatted fourth and flatted seventh.

A minor version of the pentatonic scale is obtained by using the same notes as before, but starting one step lower to obtain the tonic note: {A, C, D, E, G}. This scale is used in jazz and in Appalachian folk music.

Further pentatonic musical traditions

The pentatonic scale is very common in Scottish music. Some scholars believe that English folk music was likewise at one time a pentatonic tradition; for the reasoning behind this claim, see Folk music.

The major pentatonic scale is the basic scale of the music of China and one of the most important scales in jazz.

Composers of Western classical music have occasionally used the pentatonic scale for special effects. Maurice Ravel used it as a pastiche of Chinese music in "Laideronette, Emperatrice des Pagodes", a movement from his "Ma mere l’oye" (Mother Goose) suite for orchestra. Frédéric Chopin wrote the right hand piano part of his Etude Op. 10 no. 5 in the major G flat pentatonic scale--hence, using only the black keys.