Flat (music)

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Figure 1. The notes A flat and A double flat on the treble clef.
Example of flats in music on piano. An A, then A.

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In music, flat, or bemolle (Italian: "soft B", "to make minor" [as, e.g., a minor third]), means "lower in pitch"; the flat symbol lowers a note by a half step.[1] Intonation may be flat, sharp, or both, successively or simultaneously. More specifically, in music notation, flat means, "lower in pitch by a semitone (half step)," and has an associated symbol (), which is a stylised lowercase "b" that may be found in key signatures or as an accidental, as may sharps. The Unicode character ♭ (U+266D) is the flat sign. Its HTML entity is ♭.

Under twelve tone equal temperament, C flat for instance is the same as, or enharmonically equivalent to, B natural, and G flat is the same as 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), or a flat to indicate a note is lowered 70.6 cents.[2]

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 (in for instance microtonal music notation) one will encounter half, or three-quarter, or otherwise altered flats. The Unicode character '𝄫' (U+1D12B) represents the double flat sign.

Although very uncommon and only used in modern classical music, a triple flat (triple flat) can sometimes be found. It lowers a note three semitones.[3]

The note A flat is shown in musical notation in Figure 1, together with A double flat.

In tuning, flat can also mean "slightly lower in pitch". If two simultaneous notes are slightly out of tune, the lower-pitched one (assuming the higher one is properly pitched) is said to be flat with respect to the other.

C-major/a-minor key signature.

The order of the flats in key signature notation B, E, A, D, G, C, and F. A mnemonic for this is: Before Eating A Doughnut Get Coffee First.

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

A 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 flat, or sesquiflat, is represented by a half flat and a regular flat (three quarter flat).

See also[edit]


  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. ^ 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."
  3. ^ Extremes of Conventional Music Notation.