Editing Flat (music) (section)

== Flats in key signatures ==
{| style="background:white;border:none;"
|-
|{{spaces|3}}
| colspan="3" align="center" | '''{{vanchor|Order of flats}} in [[key signatures]]'''
|-
|{{spaces|3}}
| colspan="2" |
{| class="wikitable"
|- style="vertical-align:bottom;"
! Number<br />of flats !! [[Major scale|Major key]]!! [[Scale (music)|Scale]]!! [[Minor scale|Minor key]]
|-
| align="center" | 0 || [[C major]] || align="center" |  {{color|lightgrey|— ''none'' — }}  || [[A minor]]
|-
| align="center" | 1 || [[F major]] || B♭ || [[D minor]]
|-
| align="center" | 2 || [[B-flat major|B♭ major]]
| B♭, E♭
| [[G minor]]
|-
| align="center" | 3 || [[E-flat major|E♭ major]]
| B♭, E♭, A♭
| [[C minor]]
|-
| align="center" | 4 || [[A-flat major|A♭ major]]
| B♭, E♭, A♭, D♭
| [[F minor]]
|-
| align="center" | 5 || [[D-flat major|D♭ major]]
| B♭, E♭, A♭, D♭, G♭
| [[B-flat minor|B♭ minor]]
|- style="background:lightgrey;"
| align="center" | 6 || [[G-flat major|G♭ major]]
| B♭, E♭, A♭, D♭, G♭, '''C♭'''*
| [[E-flat minor|E♭ minor]]
|- style="background:lightgrey;"
| align="center" | 7 || [[C-flat major|C♭ major]]
| B♭, E♭, A♭, D♭, G♭, '''C♭'''*, '''F♭'''*
| [[A-flat minor|A♭ minor]]
|}
|-
|
|
:The last two rows are shaded, indicating keys that are generally avoided, in<br />part because they use inconvenient [[enharmonic]] notes, denoted with "*".
:In the standard tuning system of [[12 equal temperament]], the key of [[C-flat major|C{{music|flat}} major]], with 7 flats is enharmonically equivalent with [[B major]], which only requires 5&nbsp;sharps.
|
|}

The order of flats in key signatures is
: B♭, E♭, A♭, D♭, G♭, C♭, F♭
The corresponding order of keys also follows the [[circle of fifths]] sequence:
: F, B♭, E♭, A♭, D♭, G♭, C♭
Starting with no flats or sharps (C major), adding the first flat (B♭) indicates [[F major|F&nbsp;major]]; adding the next (E♭) indicates B♭ major, and so on, backwards through the circle of fifths.

Some keys (such as C♭ major with seven flats) may be written as an enharmonically equivalent key (B major with five sharps in this case). In rare cases the flat keys may be extended further:
: F♭ → B𝄫 → E𝄫 → A𝄫 → D𝄫 → G𝄫 → C𝄫
requiring double flats in the key signature. These are generally avoided as impractical, and the simpler, equivalent key signature is used instead. This principle applies similarly to the sharp keys.

The staff below shows a key signature with three flats ([[E flat major|E{{music|b}} major]] or its [[Relative key|relative minor]] [[C minor]]), followed by a note with a flat preceding it: The flat symbol placed on the note indicates that it is a D♭.

:<score>{ \omit Score.TimeSignature \relative c'' { \key es \major des1 } }</score>

In standard 12 tone equal temperament tuning, lowering a note's pitch by a semitone results in a note that is [[Enharmonic|enharmonically equivalent]] to the adjacent named note. In this system, B{{Music|flat}} and A{{Music|sharp}} are considered to be equivalent. In other, non-standard [[tuning system]]s, however, this is not the case.