Accidentals
Five signs that retune a note — all on the same note, all playable: first plain, then with the sign.
An accidental changes the pitch of the note it stands in front of. By how much is the same every time: a semitone, or two for the double signs. That cannot be explained, only heard — which is why every picture on this page shows the same note twice, first plain and then with the sign before it.
The note is always the same, and that is deliberate: it leaves the sign as the only thing that differs. A sharp raises by a semitone, a flat lowers by one, the double sharp raises by two, the double flat lowers by two. The natural is the only one of the five with no interval of its own — it takes back whatever came before and restores the plain note.
Sharp
Raises the note by a semitone. The most common of the five: it stands in the key signature of sharp keys and inside the bar wherever a note from outside the key is needed. In the name of the raised note it shows up as an ending — the plain note name plus a syllable.
First the note without a sign, then the same note with it
Flat
Lowers the note by a semitone, the counterpart to the sharp. In print it looks like a small letter b, which is exactly where its German name comes from. It stands in the key signature of flat keys and anywhere in the bar where a note is wanted a semitone lower.
First the note without a sign, then the same note with it
Natural
Takes an accidental back and restores the plain note. It is the only one of the five with no fixed interval: after a sharp it lowers by a semitone, after a double sharp by two. It works on whatever is in force — on the accidental in the bar as much as on the key signature.
First the note without a sign, then the same note with it
Double sharp
Raises the note by two semitones, that is by a whole tone. It looks like a small cross of four wedges and appears where an already raised note has to be raised once more — in keys with many sharps and in harmonies aiming at a leading note. It is written so that the note name stays right, not because it is convenient.
First the note without a sign, then the same note with it
Double flat
Lowers the note by two semitones. Two flats side by side, and the same logic as the double sharp, only downwards: on the keyboard the note has a far simpler name, but in the context of the key that name would be wrong. Rare, and where it appears, for good reason.
First the note without a sign, then the same note with it
How long an accidental lasts
One sharp on the first note — all four notes of the bar sound raised
This is where nearly everyone misreads once: an accidental applies not just to the note beside it but up to the next barline — to every further note of the same pitch in that bar. In the picture only the first note carries a sharp, and yet all four notes of the first bar sound raised. The second bar has no sign, and there the note sounds plain again.
That is why nobody writes the sharp four times over. And it is why good editions sometimes print a natural where it would strictly be unnecessary: in the next bar, for safety, so that nobody still has the sharp above in their ear. Such a sign is called a courtesy or cautionary accidental and is occasionally put in brackets.
The sign at the start of the line
One sharp at the start of the line — four raised notes in two registers
Right at the front, immediately after the clef, stands something that looks exactly the same and yet works differently: the key signature. It does not last until the barline but for the whole piece, in every octave and every bar — until a new key is written in.
The picture has a single sharp at the start. Four notes follow in two different registers, and all four sound raised although none of them carries a sign. That is the whole difference: an accidental inside the bar applies to one pitch until the barline, a key signature to one note name in every register.
Which key carries how many signs
How many sharps or flats stand at the start of the line, and in what order, is decided by the key. That is not here but with the Tonarten — every key has its signature pictured there, and the circle of fifths shows why the order is what it is. Which notes the scale is then built from is with the Tonleitern.
Music symbols · Tonarten · Music notation glossary
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See AnotonaEvery note on this page is computed, not typed in — following the rule that also makes F# major spell its seventh degree E#, not F.