Key signatures
A key signature is the set of sharps or flats written at the start of every staff. Each sharp or flat applies to every note with that letter name, in every octave, until the key signature changes. It tells you which key the music is in—or rather, which pair of keys: a major key and its relative minor share the same signature.
The order of sharps and flats
Sharps and flats always appear in the same order, so you can recognize a key signature by counting them.
- Sharps: F♯, C♯, G♯, D♯, A♯, E♯, B♯ — “Father Charles Goes Down And Ends Battle”.
- Flats: B♭, E♭, A♭, D♭, G♭, C♭, F♭ — the same order backwards: “Battle Ends And Down Goes Charles’ Father”.
How to name the major key
- Sharp keys: go up a half step from the last sharp. The last sharp is F♯ → G major; the last sharp is C♯ → D major.
- Flat keys: the second-to-last flat names the key. B♭ and E♭ → B♭ major; B♭, E♭, A♭ and D♭ → A♭ major.
- Two keys to learn by heart: no sharps or flats is C major, and one flat is F major.
Major or minor?
The relative minor starts on the 6th note of the major scale (a minor third below the tonic) and uses the same key signature: two sharps are D major or B minor. To decide between them, look at the music itself: pieces usually begin and end on the tonic chord, and minor keys often raise the 7th note with an accidental (A♯ in B minor).
All key signatures
| Key signature | Major key | Relative minor |
|---|---|---|
| no sharps or flats | C major | A minor |
| 1 sharp (F♯) | G major | E minor |
| 2 sharps | D major | B minor |
| 3 sharps | A major | F♯ minor |
| 4 sharps | E major | C♯ minor |
| 5 sharps | B major | G♯ minor |
| 6 sharps | F♯ major | D♯ minor |
| 7 sharps | C♯ major | A♯ minor |
| 1 flat (B♭) | F major | D minor |
| 2 flats | B♭ major | G minor |
| 3 flats | E♭ major | C minor |
| 4 flats | A♭ major | F minor |
| 5 flats | D♭ major | B♭ minor |
| 6 flats | G♭ major | E♭ minor |
| 7 flats | C♭ major | A♭ minor |
Practice questions
Tap an answer to see the explanation.
What is the major key of this key signature?
Answer: D major
This key signature has 2 sharps; the major key is D major.
What is the major key of this key signature?
Answer: B♭ major
This key signature has 2 flats; the major key is B♭ major.
What is the minor key of this key signature?
Answer: C minor
This key signature has 3 flats; the minor key is C minor.
What is the major key of this key signature?
Answer: G major
This key signature has 1 sharp; the major key is G major.
What is the key signature of F minor?
Answer: 4 flats
The key signature of F minor is 4 flats.
What is the key signature of G♯ minor?
Answer: 5 sharps
The key signature of G♯ minor is 5 sharps.
What is the key signature of E♭ major?
Answer: 3 flats
The key signature of E♭ major is 3 flats.
Which sharp is added sixth in key signatures?
Answer: E♯
Sharps are added in the order F♯, C♯, G♯, D♯, A♯, E♯, B♯; number 6 is E♯.
The circle of fifths: how keys are related →
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