Enharmonics: one sound, several names
Music theory · Notes and the staff · Level 3 · 8 min
The black key between C and D can be called C♯ or D♭. On a piano both names mean the same pitch: they are enharmonic equivalents. Every key on the keyboard has two or three possible names.
| Key | Enharmonic names |
|---|---|
| black key between C and D | C♯ = D♭ (= B𝄪) |
| black key between F and G | F♯ = G♭ (= E𝄪) |
| white key F | F = E♯ = G𝄫 |
| white key C | C = B♯ = D𝄫 |
| white key E | E = F♭ = D𝄪 |
M:4/4 L:1/4 K:C ^C2 _D2 | ^E2 F2 | B2 _c2 | ^^F2 G2 |]
Each bar plays the same pitch twice, spelled two different ways.
So why two names?
Because the spelling of a note tells you its function. A few principles:
- A scale uses each letter exactly once. The D major scale is spelled D E F♯ G A B C♯ — not D E G♭ G…, which would skip F and repeat G.
- Intervals depend on letter names. C–E♭ is a (minor) third, C–D♯ an (augmented) second, even though they sound identical on the piano.
- Melodic direction: a rising chromatic line is usually spelled with sharps (C, C♯, D), a falling one with flats (D, D♭, C).
Did you know? On a piano tuned in equal temperament the octave is divided into twelve identical semitones, so C♯ and D♭ are exactly the same pitch. But violinists and singers, who can adjust their tuning, sometimes intone them very slightly differently depending on the context.
Method: to find a note's enharmonic, count semitones. E♯ = E + 1 semitone = F. C♭ = C − 1 semitone = B. B𝄪 = B + 2 semitones = C♯.
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