Key Signatures
Explore every major and minor key with its sharps, flats, diatonic chords, relative and parallel keys. Then practice with two trainer modes - count the accidentals or identify the key from its signature.
Major keys
Minor keys
C Major
C · D · E · F · G · A · B
Accidentals
no sharps or flats
Relative key
A Natural Minor
Parallel key
C Natural Minor
Diatonic chords
- IC
- iiDm
- iiiEm
- IVF
- VG
- viAm
- vii°B°
What is a key signature?
A key signature is a group of sharps or flats placed at the start of every staff line. It tells you which notes are altered throughout the piece, so the music doesn't need an accidental in front of every affected note.
Major and minor keys come in pairs that share the same signature - they are called relative keys. C major and A minor both have no sharps or flats; G major and E minor both have one sharp; and so on around the circle of fifths.
Order of accidentals
Sharps appear in this order
F♯ · C♯ · G♯ · D♯ · A♯ · E♯ · B♯
Mnemonic: "Father Charles Goes Down And Ends Battle."
Flats appear in this order
B♭ · E♭ · A♭ · D♭ · G♭ · C♭ · F♭
Mnemonic: "Battle Ends And Down Goes Charles' Father" (reverse of sharps).
Frequently asked questions
- What does the key signature tell me?
- It lists every note that is sharp or flat throughout a piece, in a fixed canonical order. Reading it tells you the key without scanning the whole melody.
- Why does each key always have the same number of sharps or flats?
- Because the major scale formula (W-W-H-W-W-W-H) forces a specific set of accidentals from each tonic. Going up by a fifth adds one sharp; going up by a fourth adds one flat. That is the circle of fifths.
- What is a relative key?
- A major key and the minor key that share the same signature are relative - for example C major and A minor. Their tonics sit a minor third apart.
- How do I find a minor key's signature?
- Look up its relative major: count three semitones up from the minor tonic. The signature of that major key is also the signature of the minor key.