Fundamentals
Key Signatures and the Order of Sharps and Flats
Sharps arrive in the order F C G D A E B and flats in reverse. The order is the circle of fifths written out, one signature at a time.
Accidental
A sign before a note that raises or lowers its pitch by a semitone, or cancels an earlier sign, relative to the key signature.
Also called: accidentals, chromatic alteration
An accidental is a sign placed before a note head that changes its pitch relative to the key signature. The sharp (♯) raises a note by one semitone, the flat (♭) lowers it by one semitone, and the natural (♮) cancels an earlier sharp or flat. Double sharps and double flats move a note by two semitones. Accidentals written in the music, rather than in the key signature, are called incidental, and by common convention they apply to that pitch for the rest of the measure. In C major, F♯ needs an incidental sharp, while in G major the sharp on F is already in the key signature, so no sign is needed. Some editors add courtesy accidentals in brackets as a reminder.
Related terms
- Key signatureThe sharps or flats written after the clef that set which notes are altered throughout a piece unless cancelled.
- Sharp (♯)An accidental that raises a note by one semitone, written as ♯ before the note head.
- Flat (♭)An accidental that lowers a note by one semitone, written as ♭ before the note head.
- Natural sign (♮)A sign that cancels a previous sharp or flat, returning a note to the pitch its letter name gives on the white keys.