# Sharp (music)

In music, sharp – eqv. dièse (from French) or diesis (from Greek δίεσις) – means higher in pitch. The sharp symbol, ♯, indicates that the note to which the symbol is applied is played one semitone higher. The opposite of sharp is flat, indicating a lowering of pitch. The ♯ symbol derives from a square form of the letter b (see History of notation of accidentals for more information).

## Examples

The sharp symbol is used in key signatures or as an accidental applied to a single note. The staff below has a key signature with three sharps (A major or its relative minor, F♯ minor). The sharp symbol placed on the note indicates that it is an A♯ instead of an A♮.
In twelve-tone equal temperament tuning (the predominant system of tuning in Western music), raising a note's pitch by a semitone results in a note that is enharmonically equivalent to another named note. For example, A♯ and B♭ would be equivalent. This is not the case in most non-standard tuning systems.

## Variants

A double sharp is indicated by the symbol and raises a note by two chromatic semitones. Historically, a double sharp was sometimes written , or .
A half sharp, or demisharp raises a note by approximately a quarter tone. A sharp-and-a-half, three-quarter-tone sharp, or sesquisharp raises a note by three quarter tones.
A triple sharp ( or ♯) is extremely rare. It would raise a note by three semitones (a whole tone plus a semitone). The B below would be enharmonic with D natural.

## Key signature

In a key signature, sharps or flats are placed to the right of the clef. The pitches indicated apply in every measure and octave.
| Number of sharps | Major key | Sharp notes | Minor key |
| 0 | C major | – | A minor |
| 1 | G major | F♯ | E minor |
| 2 | D major | F♯, C♯ | B minor |
| 3 | A major | F♯, C♯, G♯ | F♯ minor |
| 4 | E major | F♯, C♯, G♯, D♯ | C♯ minor |
| 5 | B major | F♯, C♯, G♯, D♯, A♯ | G♯ minor |
| 6 | F♯ major | F♯, C♯, G♯, D♯, A♯, E♯ | D♯ minor |
| 7 | C♯ major | F♯, C♯, G♯, D♯, A♯, E♯, B♯ | A♯ minor |
The order of sharps in key signatures is F♯, C♯, G♯, D♯, A♯, E♯, B♯. Starting with no sharps or flats (C major), adding the first sharp (F♯) indicates G major, adding the next (C♯) indicates D major, and so on through the circle of fifths.
Some keys (such as C♯ major with seven sharps) may be written as an enharmonically equivalent key (D♭ major with five flats in this case). In rare cases, the sharp keys may be extended further, G♯ → D♯ → A♯ → E♯ → B♯ → F → C, requiring double sharps in the key signature: F, C, G, D, A, E, B.

## Accidental

When used as an accidental, the sharp sign applies to the note on which it is placed, and to subsequent similar notes in the same measure and octave. In modern notation accidentals do not apply to notes in other octaves, but this was not always the convention.
If a sharp is used as an accidental, it can be cancelled on a subsequent similar note in the staff, measure and octave by using a flat (♭) or a natural (♮).

## Unicode

In Unicode, assigned sharp signs are as follows:
* U+266F ♯ MUSIC SHARP SIGN (&sharp;)
* U+1D12A 𝄪 MUSICAL SYMBOL DOUBLE SHARP
* U+1D130 𝄰 MUSICAL SYMBOL SHARP UP
* U+1D131 𝄱 MUSICAL SYMBOL SHARP DOWN
* U+1D132 𝄲 MUSICAL SYMBOL QUARTER TONE SHARP

## Other notation and usage

* The sharp symbol (♯) resembles the number (hash) sign (#), in that both have two intersecting sets of parallel double lines. While the number sign may have a pair of horizontal lines, the sharp sign has a pair of slanted lines that rise from left to right instead, to avoid obscuring the staff lines. The other set of parallel lines are vertical in the sharp sign, while the number sign (#) may have slanted lines instead. It is also etymologically independent from the number sign. Likewise, while the double-sharp sign resembles a bold-face lower-case x it needs to be typographically distinct.
* Historically, lowering a double sharp to a single sharp could be notated using a natural and sharp sign (♮♯) or vice-versa (♯♮) instead of the conventional sharp sign (♯), but the natural sign is often omitted in modern notation. The same principle applies when canceling a triple sharp. The combination ♮♯ can be also written when changing a flat to a sharp.
* In environments where the symbol is not supported a double sharp can be written using two single sharp signs (♯♯), hash signs (##) or a lower-case letter x. Likewise, a triple sharp can be written as ♯♯♯.
* To allow extended just intonation, composer Ben Johnston uses a sharp to indicate a note is raised 70.6 cents (ratio 25:24).