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Notes A-flat and A double-flat on the treble clef
C-major/a-minor key signature

In music, flat, or bemolle (Italian: "soft B") means "lower in pitch". In music notation, the flat symbol, , derived from a stylised lowercase "b", lowers a note by a half step (semitone).[1][2] Intonation or tuning is said to be flat when it is below the intended pitch.

Flat accidentals are used in the key signatures of F major/D minor, B major/G minor, E major/C minor, A major/F minor, D major/B minor, and the less frequently used keys of G major/E minor, C major/A minor. The order of flats in the key signatures of music notation, following the circle of fifths, is B, E, A, D, G, C and F (mnemonics for which include Battle Ends And Down Goes Charles' Father and Before Eating A Doughnut Get Coffee First).

Half-tone between C and D, 100 cents About this sound Play 
Quarter tone between C and Dthree quarter flat (flat and a half), 50 cents About this sound Play 
Three-quarter tone between C and Dhalf flat (half flat), 150 cents About this sound Play 

The Unicode character ♭ (U+266D) can be found in the block Miscellaneous Symbols; its HTML entity is ♭.

Under twelve tone equal temperament, C for instance is the same as, or enharmonically equivalent to, B (B-natural), and G is the same as F (F-sharp). In any other tuning system, such enharmonic equivalences in general do not exist. To allow extended just intonation, composer Ben Johnston uses a sharp as an accidental to indicate a note is raised 70.6 cents (ratio 25:24), and a flat to indicate a note is lowered 70.6 cents.[3]

Double flats also exist, which look like double flat (similar to two flats, ) and lower a note by two semitones, or a whole step. Less often (for instance in microtonal music notation) one will encounter half, or three-quarter, or otherwise altered flats. The Unicode character 𝄫 (U+1D12B) in the Musical Symbols block represents the double-flat sign.

Although very uncommon, a triple flat (triple flat) can sometimes be found.[4] It lowers a note three semitones.

A quarter-tone flat or half flat, indicating the use of quarter tones, may be marked with various symbols including a flat with a slash (flat stroke) or a reversed flat sign (half flat).About this sound Play  A three-quarter-tone flat, flat and a half or sesquiflat, is represented by a half flat and a regular flat (three quarter flat).

See alsoEdit


  1. ^ Benward & Saker (2003). Music in Theory and Practice, Vol. 1, p. 6. McGraw-Hill, Seventh edition. "Flat ()—lowers the pitch a half step."
  2. ^ Flat, Glossary, Naxos Records
  3. ^ John Fonville. "Ben Johnston's Extended Just Intonation- A Guide for Interpreters", p. 109, Perspectives of New Music, Vol. 29, No. 2 (Summer, 1991), pp. 106–137. "...the 25/24 ratio is the sharp () ratio...this raises a note approximately 70.6 cents."
  4. ^ Byrd, Donald (September 2016). "Extremes of Conventional Music Notation". Indiana University Bloomington. Retrieved 4 November 2016. 

External linksEdit