Enharmonic notes: same sound, different name

Some notes have two names. The black key just above C is called C♯ when you think of it as C raised, and D♭ when you think of it as D lowered. The two names sound exactly alike on a piano. Such a pair is called an enharmonic pair, and each note is the enharmonic equivalent of the other. This page explains why we have two names, when to use each and which pairs can be tricky.

What does enharmonic mean?

Two notes are enharmonic if they have the same pitch but different names. They are played with the same key on a piano, the same fret on a guitar and the same fingering on most instruments. The word comes from Greek and is pronounced en-har-MON-ic. Enharmonic notes are different on the page, but equal in sound.

What are the enharmonic pairs on the piano?

Each of the five black keys has two names. The white keys have them too, because a white key can be written with a sharp or flat: E♯ is the same as F, and F♭ is the same as E. Likewise B♯ is C and C♭ is B. The table lists the most common pairs.

Why do we have two names for one note?

The names exist because of the way scales and chords are spelled. A major scale uses each letter name once, so the notes of the D♭ major scale are spelled D♭ E♭ F G♭ A♭ B♭ C, with no C♯ in it, even though D♭ and C♯ are the same key. A composer chooses the spelling that keeps the letters in order, so the music is easier to read and fits the key. This is why the same black key can be C♯ in one piece and D♭ in another.

Which spelling should I use?

Pick the name that fits the key and the music around it. In a key with sharps, such as D major, the black keys are called sharps (F♯, C♯). In a key with flats, such as F major or B♭ major, they are called flats (B♭, E♭). Within a piece, the spelling also follows the direction of the melody: a rising line is often written with sharps, and a falling one with flats. Rules vary, and good judgment matters more than the rule.

• Sharp keys: use sharps (G, D, A, E, B major).
• Flat keys: use flats (F, B♭, E♭, A♭ major).
• Rising chromatic lines: often sharps.
• Falling chromatic lines: often flats.

What are enharmonic keys?

Whole keys can be enharmonic too. F♯ major (six sharps) and G♭ major (six flats) sound the same, and so do C♯ major and D♭ major. Their key signatures look different, but they sit at the same point on the circle of fifths. A composer picks the one that has fewer accidentals or fits the other keys in the piece. For the key signatures, see key signatures.

Are enharmonic notes always the same pitch?

On the piano and in most modern music, yes. The piano is tuned in equal temperament, where the octave is divided into 12 equal half steps, and so C♯ and D♭ share a key. On a violin or in a choir, however, the players can make small adjustments, and some people hear a slight difference between C♯ and D♭ in just intonation. For an ordinary student, it is correct to say that they sound the same.

What about octave numbers?

Take care with B♯ and C♭, because they cross the border between octaves. B♯3 is the same key as C4, and C♭4 is the same key as B3. In scientific pitch notation the octave number changes at C, so the spelling matters for the number. This does not usually cause trouble outside special cases.

To see the keys involved, look at the piano keys page, and for the effect of the signs themselves see sharps and flats. The distance between neighbouring keys is a half step.

Check yourself

Related pages

• Sharps, flats and naturals in music
• Half steps and whole steps (semitones and tones)
• Piano keys labeled: every note on the keyboard
• Key signatures: how to read every key
• Circle of fifths: how it works and its uses
• Chromatic scale: all 12 notes explained