How to use
- Tap a key card to see its signature in large print, with its relative and parallel minor.
- Read the rule under the staff, then look at the accidentals again on the other clef.
- Press Quiz me, choose major, minor or either, and pick treble, bass or both clefs.
- Answer ten questions. Each answer explains the shortcut so a wrong guess teaches you the rule.
All 15 key signatures
| Key | Signature | Accidentals in order | Relative minor | Parallel minor |
|---|---|---|---|---|
| C major | no sharps or flats | None | Am | Cm (3 flats) |
| G major | 1 sharp | F♯ | Em | Gm (2 flats) |
| D major | 2 sharps | F♯ C♯ | Bm | Dm (1 flat) |
| A major | 3 sharps | F♯ C♯ G♯ | F♯m | Am (no sharps or flats) |
| E major | 4 sharps | F♯ C♯ G♯ D♯ | C♯m | Em (1 sharp) |
| B major | 5 sharps | F♯ C♯ G♯ D♯ A♯ | G♯m | Bm (2 sharps) |
| F♯ major | 6 sharps | F♯ C♯ G♯ D♯ A♯ E♯ | D♯m | F♯m (3 sharps) |
| C♯ major | 7 sharps | F♯ C♯ G♯ D♯ A♯ E♯ B♯ | A♯m | C♯m (4 sharps) |
| F major | 1 flat | B♭ | Dm | Fm (4 flats) |
| B♭ major | 2 flats | B♭ E♭ | Gm | Bbm (5 flats) |
| E♭ major | 3 flats | B♭ E♭ A♭ | Cm | Ebm (6 flats) |
| A♭ major | 4 flats | B♭ E♭ A♭ D♭ | Fm | Abm (7 flats) |
| D♭ major | 5 flats | B♭ E♭ A♭ D♭ G♭ | Bbm | Dbm (8 flats, theoretical) |
| G♭ major | 6 flats | B♭ E♭ A♭ D♭ G♭ C♭ | Ebm | Gbm (9 flats, theoretical) |
| C♭ major | 7 flats | B♭ E♭ A♭ D♭ G♭ C♭ F♭ | Abm | Cbm (10 flats, theoretical) |
Order of sharps and flats
Sharps are always added in the same order: F, C, G, D, A, E, B. Flats come in the reverse order: B, E, A, D, G, C, F. A common phrase for the sharps is Father Charles Goes Down And Ends Battle, and reading it backwards gives the flats: Battle Ends And Down Goes Charles Father. Each new sharp is a perfect fifth above the last one, which is exactly why the keys line up around the circle of fifths.
Two shortcuts for naming a key
- Sharps: find the last sharp in the signature. The major key is a half step above it. Three sharps ending on G sharp point to A major.
- Flats: find the second-to-last flat. That flat names the major key. Four flats, B E A D, point to A flat major, because A is the second-to-last. One flat is simply F major.
Relative and parallel keys
A relative minor shares its major key signature. It starts on the sixth note of the major scale, a minor third below the major tonic, so A minor shares C major's empty signature. A parallel minor shares the same tonic letter but not the signature: C minor has three flats while C major has none. Parallel minors are three steps toward the flat side of the circle from their major.
Why 15 and not 12
There are seven sharp keys, seven flat keys and C major with no accidentals, which makes 15 written signatures. On the keyboard three pairs sound identical: B major and C flat major, F sharp major and G flat major, C sharp major and D flat major. Players usually choose the version with fewer accidentals.
Minor keys and accidentals
The signature shows the natural minor scale. In harmonic and melodic minor the seventh note, and sometimes the sixth, are raised, and those changes appear in the music as accidentals rather than in the signature. A key signature alone does not say whether a piece is major or minor, so listen to the ending or check the final chord.
Frequently asked questions
How many key signatures are there?
There are 15 written major key signatures: seven with sharps, seven with flats and C major with none. Each has a relative minor, so there are 15 minor signatures too. Because three pairs are enharmonic, there are 12 distinct keys on a keyboard.
How do I find the major key from sharps?
Find the last sharp in the signature and go up a half step. If the last sharp is F sharp, the key is G major. If it is D sharp, the key is E major.
How do I find the major key from flats?
Find the second-to-last flat. That flat names the key. B flat and E flat mean B flat major. The exception is one flat, which is F major.
What is the relative minor of a major key?
The relative minor starts on the sixth degree of the major scale and shares its key signature. A minor is the relative minor of C major, and E minor is the relative minor of G major.
What is a parallel key?
A parallel key shares the same starting note but has a different key signature. C major and C minor are parallel keys. C major has no sharps or flats and C minor has three flats.
Does the key signature tell me if a piece is major or minor?
No. Every signature fits one major key and its relative minor. To tell them apart, look at the first and last chords and listen for the note that feels like home.