Chord progressions also often move between chords whose roots are related by perfect fifth, making the circle of fifths useful in illustrating the 'harmonic distance' between chords. These closely-related keys are a fifth apart from each other and are therefore adjacent in the circle of fifths. Tonal music often modulates to a new tonal center whose key signature differs from the original by only one flat or sharp. Major and minor keys that have the same key signature are referred to as relative major and relative minor of one another. The circle diagram shows the number of sharps or flats in each key signature, with the major key indicated by a capital letter and the minor key indicated by a lower-case letter. Structure and use Diatonic key signatures Įach of the twelve pitches can serve as the tonic of a major or minor key, and each of these keys will have a diatonic scale associated with it. Moving counter-clockwise from C could be thought of as descending by a fifth to F, or ascending by a fourth to F.Ĭircle of fifths counterclockwise within one octave Moving counterclockwise, the pitches descend by a fifth, but ascending by a perfect fourth will lead to the same note an octave higher (therefore in the same pitch class). Starting at any pitch and ascending by a fifth generates all twelve tones before returning to the beginning pitch class (a pitch class consists of all of the notes indicated by a given letter regardless of octave-all 'C's, for example, belong to the same pitch class). Some keys (at the bottom of the circle) can be notated either in sharps or in flats. Similarly, proceeding counterclockwise from the top of the circle, the notes change by descending fifths and the key signatures change accordingly: the key of F has one flat, the key of B ♭ has 2 flats, and so on. The key signatures associated with those pitches also change: the key of G has one sharp, the key of D has 2 sharps, and so on. Proceeding clockwise, the pitches ascend by fifths. The top of the circle shows the key of C Major, with no sharps or flats. Twelve equal-temperament fifths lead to a note exactly seven octaves above the initial tone-this results in a perfect fifth that is equivalent to seven equal-temperament semitones. To adjust for this, instruments are generally tuned with the equal temperament system. Using the system of just intonation, a perfect fifth consists of two pitches with a frequency ratio of 3:2, but generating twelve successive perfect fifths in this way does not result in a return to the pitch class of the starting note. Its design is helpful in composing and harmonizing melodies, building chords, and modulating to different keys within a composition. Musicians and composers often use the circle of fifths to describe the musical relationships between pitches. The circle of fifths organizes pitches in a sequence of perfect fifths, generally shown as a circle with the pitches (and their corresponding keys) in a clockwise progression. It is usually illustrated in the form of a circle. This order places the most closely related key signatures adjacent to one another. Continuing the pattern from F returns the sequence to its starting point of C. If C is chosen as a starting point, the sequence is: C, G, D, A, E, B (=C ♭), F ♯ (=G ♭), C ♯ (=D ♭), A ♭, E ♭, B ♭, F.

(This is strictly true in the standard 12-tone equal temperament system - using a different system requires one interval of diminished sixth to be treated as a fifth). In music theory, the circle of fifths is a way of organizing the 12 chromatic pitches as a sequence of perfect fifths. Circle of fifths showing major and minor keys