Key Signature Symbols

What are Key Signature Symbols?


For musicians an important thing to know is the key that the music should be played or sung in. This can be determined by the key signature. The key signature is a group of flat or sharps next to the clef at the beginning of the line of music. Key signatures can change throughout a song, so the musicians should pay attention for possible changes.

Key signatures date back to the medieval times. During this time there was music written with a sort of signature indicating that there would be one flat throughout the piece. It wasn’t until later in the 16th century that multiple flats began appearing in the signature. It would be another hundred years before sharps were used as part of the key signature.

Even still, since these signatures usually denote the major key the piece is played in, some Baroque pieces are written in the minor key. This means that while the signature may show one thing, there are accidentals, single notes either flattened or sharped, throughout the piece making it into a different minor key.


The number of flats, which look similar to a lower case b, or sharps, which look like a number signal (#) will determine the key that the piece is in. If the key signature has flats the major key called by the name of the next to last flat. For example if there are two flats in the signature (B and E) the major key is called B flat.

For a key signature that has sharps the major key name is the note above the last sharp. For example the key of G has one sharp in it, the F sharp. In the case of the sharp key signature the name for the signature takes into account the already sharped notes. An example would be the key of C#. This key has 7 sharps, the last of which is B. Since C is the note above B and already has a sharp included on it, the name of the key takes on the sharp making it C sharp.

When a musician reads a piece of music with a specified key signature all notes with in that piece of music follows the signature. In other words, a piece of music written in the key of B flat all Bs and Es in the piece are performed as B flat and E flat, lowering the note by a semitone.

The same goes for music in with sharps in the signature, only instead of lowering the note by a semitone playing the note as a sharp raises the note a semitone. There is only one true key with no key signature and that is the key of C major.

The key signature helps the musician know what the prevailing key of the piece is. It also clears the piece from having an overabundance of accidentals making the piece easier to read.