Sharps, Flats and Naturals

What you’ll learn

A black key has no letter of its own, so it borrows one from a neighbor. The key just above F is F sharp (F♯): a sharp raises a note by a half step. The same key is just below G, so it’s also G flat (G♭): a flat lowers a note by a half step.

Together, sharps, flats and naturals are called accidentals. On the staff, the sign goes just before the note, on the same line or space. You say it after the letter: “F sharp”.

A sign lasts until the end of the measure. A later note on the same line or space in that measure keeps it, even with no sign of its own. A natural sign (♮) cancels it, and the next bar line cancels it too.

Worked example

Read this measure of 4/4, one note at a time:

1. The first note sits on the middle line, B, with a flat in front: B flat.
2. The second is in the space above: C.
3. The third is B again, with no sign. The flat from the first note lasts to the end of the measure, so it’s still B flat.
4. The last note is in the space below: A.

So the measure reads B♭, C, B♭, A. In the next measure, a B with no sign would be plain B again: the bar line cancels the flat.

Common mistakes

• Writing the sign after the note. You say “B flat”, letter first, but on the staff the sign always goes before the note.
• Forgetting that a sign lasts. A sharp or flat keeps working for the rest of the measure on that line or space, even when the later notes have no sign.
• Carrying it into the next measure. The bar line cancels every accidental. If the composer wants it again, they write it again.
• Applying it to another octave. An accidental only affects notes on the same line or space. A sharp on the F in the bottom space doesn’t change the F on the top line.
• Thinking every sharp is a black key. There’s no black key between E and F, so E sharp is played on the F key, and C flat on the B key.

How the lesson works

Below the staff there’s the same keyboard as in half steps and whole steps, and it lights up to show where each note lives. There are three tasks:

1. What note is this? A note appears on the staff, usually with a sign in front of it. Choose the sign (or no sign), then the letter. About one note in four has no sign, so look before you answer.
2. Does the sign still count? A measure shows a sharp, then the same note again. Say whether the sharp still counts, or a natural has cancelled it.
3. Write it. In the editor, pick a sign and then place the note: B flat, F sharp, then C.

For every sign in one place, see music symbols. Next, the signs build a scale: build a major scale.