Key signatures
A key signature is the set of sharps or flats written after the clef at the start of every line of music. Each of those notes is played sharp or flat all the way through, in every octave, and together they name the key. There are 15, from seven flats to seven sharps, and each one is shared by a major key and its relative minor.
D major / B minor
2 sharps: F♯ and C♯
The last sharp is C♯, and a half step up is D: D major, or B minor.
Name the key from its signature
A key signature appears on the treble or bass staff: tap its major key. Each answer plays the key’s chord, and the score at the end counts how many you got and how long each took.
Ten key signatures on the treble and bass staff. Name each one’s major key as fast as you can.
Key signature chart
All fifteen on the treble staff, with the major key and the relative minor each one stands for. Tap a key for its scale, chords and a beat in it.
Sharp keys
Flat keys
The order of sharps and flats
Sharps join a key signature in the order F♯ C♯ G♯ D♯ A♯ E♯ B♯, each a fifth above the last: G major has F♯, D major adds C♯, and so on. Say “Father Charles Goes Down And Ends Battle” to remember it. A key with three sharps always has the first three, never any others.
Flats are the same letters backwards, B♭ E♭ A♭ D♭ G♭ C♭ F♭, each a fifth below the last: “Battle Ends And Down Goes Charles’ Father”. Every staff writes them in the same places, so a signature reads as a shape before you count it.
One step round the circle adds a sharp one way and a flat the other: see it on the circle of fifths.
How to read the key from a key signature
Sharps: a half step up from the last one
Name the last sharp on the right and go up a half step. Four sharps end on D♯, so the key is E major. Seven end on B♯: C♯ major.
Flats: the second-to-last one
The flat before the last names the key. Three flats are B♭ E♭ A♭, so the key is E♭ major. One flat has no flat before it: F major, the one to learn by heart.
The relative minor: three half steps down
Every signature is also a minor key’s, starting three half steps below the major one, on the sixth note of its scale. E major’s four sharps are C♯ minor’s too.
Major or minor: look at the music
The signature alone can’t tell them apart. The first and last chord usually are the key’s own, and a minor key writes its raised seventh again and again: G♯ all through a piece in A minor.
Key signatures and accidentals
A key signature holds for every bar and every octave until a new one is written, often after a double bar line. A sharp, flat or natural written just before a note is an accidental: it changes that note for the rest of its bar only.
A natural sign cancels the signature: in G major, an F with a natural before it is played F, not F♯, until the bar line. When a piece changes key, naturals cancel the old sharps or flats before the new signature is written.
The scale, chords and a beat to play in each one: every major and minor key.
Questions about key signatures
How many key signatures are there?
Fifteen: C major with no sharps or flats, seven with one to seven sharps and seven with one to seven flats. Each is shared by a major key and its relative minor, so they name 30 keys. Three pairs sound the same on a piano: B major and C♭ major, F♯ major and G♭ major, and C♯ major and D♭ major.
What key has one sharp?
G major, or its relative minor, E minor. The sharp is F♯, written on the top line of the treble staff and the fourth line of the bass staff.
What key has one flat?
F major, or its relative minor, D minor. The flat is B♭, written on the middle line of the treble staff and the second line of the bass staff.
What is the order of sharps and flats?
Sharps are added in the order F C G D A E B, which “Father Charles Goes Down And Ends Battle” remembers. Flats are the same letters backwards, B E A D G C F: “Battle Ends And Down Goes Charles’ Father”. Each new sharp is a fifth above the last, and each new flat a fifth below.
How do you tell if a key signature is major or minor?
The signature alone can’t: G major and E minor share one sharp. Look at the first and last chord, which are usually the key’s own, and for the minor key’s raised seventh: a piece in E minor writes D♯ again and again.
Why does a key signature never mix sharps and flats?
Each step round the circle of fifths changes one note of the scale: a fifth up adds a sharp, or takes away a flat, and a fifth down adds a flat. So the keys line up from seven flats to seven sharps, and none needs both.
Make a beat in any key
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