Flat

A flat lowers a note by one half step. Its sign, ♭, looks like a small pointed lowercase b, and that is no accident: it developed from a rounded letter b that medieval musicians used to mark the lower ("soft") form of the note B, today's B-flat. Written before a note, the flat is an accidental. Written after the clef at the start of each line, it is part of the key signature.

Finding flats on the piano

To play a flat, go one key to the left: the very next key, black or white. Usually that is a black key; D♭, E♭, G♭, A♭ and B♭ are all black keys. But C and F have no black key to their left, so C♭ is played on the white key B, and F♭ on the white key E. These are enharmonic equivalent spellings: two names for one key. Every black key has two names in the same way: the black key between F and G is both F♯ and G♭.

Reading flats on the staff

The flat sign sits right in front of the notehead, its round part on the same line or space as the note. It lasts until the end of the measure for that line or space, unless a natural cancels it.

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Flats in key signatures

Flats in a key signature appear in the order B, E, A, D, G, C, F, the order of sharps backward. F major has one flat (B♭); B♭ major has two (B♭ and E♭). A handy trick: with two or more flats, the second-to-last flat names the major key. F major, with its single flat, is the one to memorize.

Flat as a tuning word

Musicians also say a note is "flat" when it is slightly too low: a singer drifting flat, or a guitar string that has gone flat. That is a matter of tuning, not of written notes. The opposite is sharp.

Practice with The flat: one half step down and Half steps & whole steps.