Key signatures with 1 flat

A key signature with 1 flat is F major, or its relative minor D minor. The flat is B♭. The chart below shows it on the treble staff — free to print or download.

Which key has 1 flat?

Two keys share every signature — one major, one minor. 1 flat means F major or its relative minor D minor, and nothing else: the seven sharp keys and seven flat keys each use a different number of accidentals, so the count alone identifies the pair. The steps below show how to name it from the staff without memorising a table.

How to read it

1. Count the flats. Count the accidentals sitting between the clef and the time signature. A single flat narrows it to one major key and one relative minor.
2. Name the major key. One flat is the exception you memorise: a single B♭ is always F major.
3. Name the relative minor. Count down three semitones from F — or up six steps round the circle of fifths — to reach D minor, which shares this signature.
4. Check the melody. The signature alone cannot tell you which of the two the piece is in. Look at the first and last notes: F major and D minor use identical notes, so the music decides.

The order of flats

Flats never appear in an arbitrary order. They are added one at a time in the fixed sequence B♭ E♭ A♭ D♭ G♭ C♭ F♭, so a signature with 1 flat always uses the first one of them: B♭. That is why counting the accidentals is enough to name the key — you also know exactly which ones they will be.

Look up another key signature

By number of sharps

By number of flats

See every key laid out by its signature on the circle of fifths, test yourself with a blank circle of fifths, browse all 15 major key signatures, learn the notes on the treble clef, or read the guide to reading sheet music.