What Are Key Signatures?
Learn how sharps and flats at the beginning of a staff define the key of a piece — and memorize the order they always appear in.
What Is a Key Signature?
A key signature is a set of sharps (♯) or flats (♭) placed at the beginning of a staff, right after the clef. It tells the performer which notes are consistently raised or lowered throughout the piece.
Key Signature on the Staff
Why do we need key signatures? Without a key signature, composers would have to write a sharp or flat symbol before every affected note in the entire piece. The key signature is a convenient shorthand — write it once, and it applies to every occurrence of that note throughout.
Raise the note by a half step. A sharp key signature means certain notes are always played one semitone higher.
Lower the note by a half step. A flat key signature means certain notes are always played one semitone lower.
Order of Sharps & Flats
Sharps and flats always appear in a fixed order. Memorizing this order is essential for reading and writing key signatures.
Order of Sharps
Mnemonic: Father Charles Goes Down And Ends Battle
Order of Flats
Mnemonic: Battle Ends And Down Goes Charles' Father — the reverse of sharps!