One key, several names
There are only twelve keys in an octave, but seven letters with sharps and flats, so the same key can be written in more than one way. These are enharmonic spellings. The black key between C and D is both C♯ and D♭.
The same thing happens on white keys. E and F have no black key between them, so a half step up from E lands on a white key: E♯ is F. And a half step below C lands on B, so C♭ is B.
Sharp, flat, natural and the double versions
| Symbol | Name | Effect |
|---|---|---|
| 𝄪 | double sharp | raises by two half steps (a whole step) |
| ♯ | sharp | raises by one half step |
| ♮ | natural | cancels a sharp or flat |
| ♭ | flat | lowers by one half step |
| 𝄫 | double flat | lowers by two half steps (a whole step) |
Why not always use the simplest name?
Because each scale uses every letter once. The F♯ major scale is F♯ G♯ A♯ B C♯ D♯ E♯. Calling the last note F would repeat the letter F and skip E. The letter is chosen by the scale; the accidental is whatever makes the pitch right. A double sharp turns up in the same way: the G♯ minor scale (harmonic) has an F𝄪.
Chords work the same. A C♯ major chord is C♯ E♯ G♯: a third above C♯ must use the letter E.
Every name for every key
| Key | All the ways to write it (up to two accidentals) |
|---|---|
| 1 | C D𝄫 B♯ |
| 2 | C♯ D♭ B𝄪 |
| 3 | C𝄪 D E𝄫 |
| 4 | D♯ E♭ F𝄫 |
| 5 | D𝄪 E F♭ |
| 6 | E♯ F G𝄫 |
| 7 | E𝄪 F♯ G♭ |
| 8 | F𝄪 G A𝄫 |
| 9 | G♯ A♭ |
| 10 | G𝄪 A B𝄫 |
| 11 | C𝄫 A♯ B♭ |
| 12 | C♭ A𝄪 B |
How to practise
- Warm-up: E♯, B♯, C♭, F♭ and the sharp/flat pairs.
- Working set: any note on any letter with at most one accidental.
- Heavy lift: double sharps and double flats.
See why spelling matters in the scale spelling drill, in key signatures and in the Accidentals and Key Signatures program.
Frequently asked questions
What does enharmonic mean?
Two notes are enharmonic when they are the same key on the piano (the same pitch) but written with different names, like C♯ and D♭, or E♯ and F.
Why is E♯ a note? Isn't it just F?
E♯ sounds exactly like F. We write E♯ when the music needs the letter E, for example in the F♯ major scale, whose seventh note is E♯. Every scale uses each letter once, so the spelling is chosen by the letter that is needed, not by the key we press.
What is a double sharp?
A double sharp (𝄪) raises a note by two half steps, a whole step. F𝄪 is the same key as G. Double flats (𝄫) lower by a whole step: B𝄫 is the same key as A.
Are enharmonic notes the same sound?
On a piano, yes: one key. On a violin or in a choir singers may tune them slightly differently, and in harmony the spelling tells you the chord's role, but the piano key is one.
How do I know whether to write a sharp or a flat?
Use the key. In a sharp key (G, D, A…) write sharps; in a flat key (F, B♭, E♭…) write flats. In every scale each letter appears exactly once, so the right spelling is the one that keeps the letters in order.