Key signature · 1♭
F major key signature and D minor
F major and its relative minor, D minor, share a key signature of one flat: B♭.
- Flats1
- WhichB♭
- Relative minorD minor
- Home chordF–A–C
The key signature
The flats come right after the clef, on every line of music. In the treble clef: B♭ on the middle line. In the bass clef the same flats appear, in the same order, on the bass staff’s B.
Each one changes that letter everywhere in the piece, in every octave and on both staves: in F major, every B is flat, though no sign is written beside the note.
How to recognise it quickly
One flat, B♭, is F major (or D minor). It’s the one flat key to learn by heart, because the trick for flat keys needs at least two.
Flats always come in the same order, so one flat is always B♭:
- B♭
- E♭
- A♭
- D♭
- G♭
- C♭
- F♭
Battle Ends And Down Goes Charles’ Father: the order of flats, the order of sharps backwards.
The F major scale
F – G – A – B♭ – C – D – E – F. On the piano that’s one black key (B♭) and six white (F, G, A, C, D and E). Its home chord is F–A–C.
More on this key: the F major scale with fingering · the F major chord
D minor, the relative minor
D minor uses the same one flat, starting from D, the sixth note of F major: D – E – F – G – A – B♭ – C – D. That’s the natural minor scale. Its home chord is D–F–A.
Pieces in D minor usually raise the seventh note, C, to C♯ (the harmonic minor), so it leads up to D. That C♯ is written as an accidental, not in the key signature: the sharp beside the note is often the quickest clue that a piece is in D minor rather than F major. Pieces also often begin or end on D or its chord.
More on this key: D minor natural minor · D minor harmonic minor · the D minor chord
Music in F major and D minor
Beethoven’s Pastoral Symphony (No. 6) is in F major.
Mozart’s Fantasia in D minor, K. 397, is in D minor.
On the circle of fifths
One flat fewer is C major, a fifth higher; one flat more is B♭ major, a fifth lower. Keys next to each other on the circle of fifths share all but one note, which is why music in F major moves to them most easily.
F minor, with the same home note but a minor scale, has a different key signature: four flats, the same as A♭ major.
Quiz: name the key signature
Ten key signatures in the treble or bass clef, from all fifteen. Choose the key, or play its home note on the piano below, a MIDI keyboard or your computer keys (any octave).
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Questions
How many flats are in F major?
One flat: B♭. Every B in the piece is played flat, in every octave, unless an accidental says otherwise.
What is the relative minor of F major?
D minor. It shares the key signature (one flat (B♭)) and starts on the sixth note of the F major scale, three half steps below F.
What are the notes of the F major scale?
F, G, A, B♭, C, D, E, F.
Which key has one flat?
F major and its relative minor, D minor.
How do you recognise the F major key signature quickly?
One flat, B♭, is F major (or D minor). It’s the one flat key to learn by heart, because the trick for flat keys needs at least two.
Keys, one at a time
Pianomi, a free sight-reading app for piano, brings in key signatures one at a time and notices when you play a note as if the key signature weren’t there.