Scale degrees · F major

The ♯4 of F is B

The ♯4 (sharp four, written #4) of F is B: an augmented fourth above the root.

F — the root, 1B — the ♯4

How to find it

Count letters first, the root included: F, G, A, B. A 4th lands on B.

Then the sound: an augmented fourth is 6 semitones above F, which is exactly where B is — no sharp or flat needed.

Where you meet it

The ♯4 is the Lydian note, a tritone above the root. On a chord symbol it is usually written ♯11.

In the scale F Lydian:

F · G · A · B · C · D · E

The ♯4 in every key

KeyThe ♯4
CF♯
GC♯
DG♯
AD♯
EA♯
BE♯
F♯B♯
D♭G
A♭D
E♭A
B♭E
FB

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