Scale degrees · F major

The ♯11 of F is B

The ♯11 (sharp eleven, written #11) of F is B: an augmented eleventh above the root.

F — the root, 1B — the ♯11

How to find it

An 11th is a 4th an octave up, so it takes the 4th's letter: F, G, A, B.

Then the sound: an augmented eleventh is 18 semitones above F, which is exactly where B is — no sharp or flat needed.

Where you meet it

The ♯11 is the Lydian tension: the bright, open colour of maj7♯11 and of the Lydian dominant 7♯11.

In Fmaj7♯11:

F · A · C · E · B

The ♯11 in every key

KeyThe ♯11
CF♯
GC♯
DG♯
AD♯
EA♯
BE♯
F♯B♯
D♭G
A♭D
E♭A
B♭E
FB

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