Key Signatures: Sharps and Flats Explained
A key signature tells you which notes are sharp or flat throughout a piece. Learn the seven most common keys for beginners.
What is a key signature?
A key signature is a group of sharps (♯) or flats (♭) at the start of each stave. It tells you that those notes are raised or lowered every time they appear, in every octave, until the key changes. It saves writing an accidental in front of every F♯ in a piece in G major, for example.
The seven keys in the trainer
| Key | Signature | Relative minor | Altered notes |
|---|---|---|---|
| C major | None | A minor | — |
| G major | 1 sharp | E minor | F♯ |
| D major | 2 sharps | B minor | F♯, C♯ |
| A major | 3 sharps | F♯ minor | F♯, C♯, G♯ |
| F major | 1 flat | D minor | B♭ |
| B♭ major | 2 flats | G minor | B♭, E♭ |
| E♭ major | 3 flats | C minor | B♭, E♭, A♭ |
In treble clef
G major
D major
A major
F major
B♭ major
E♭ major
In bass clef
G major
D major
F major
B♭ major
Order of sharps and flats
Sharps are always added in this order: F C G D A E B ("Father Charles Goes Down And Ends Battle"). Flats are the reverse: B E A D G C F ("Battle Ends And Down Goes Charles's Father"). The key with one sharp is G major; two sharps D major; three sharps A major. For flats, the key with one flat is F major, and after that the key name is the second-to-last flat: two flats is B♭ major; three flats is E♭ major.
Practise reading in a key
In the note trainer, pick a key and the note you see is sharpened or flattened automatically. The feedback tells you when a note belongs to the key signature.
Frequently asked questions
How do I know which key a piece is in?
Look at the key signature and the last note of the piece. One sharp usually means G major or E minor.
Do key signatures apply to every octave?
Yes. If F is sharp in the signature, every F in every octave is sharp.
What cancels a key signature note?
A natural sign (♮) cancels it for the rest of that bar.
Why do some instruments use different key signatures?
Transposing instruments such as the B♭ clarinet read music written in a different key from the sound. See transposing instruments.