Scale degrees · E major

The ♯4 of E is A♯

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

E — the root, 1A♯ — the ♯4

How to find it

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

Then the sound: an augmented fourth is 6 semitones above E, and the A that is 6 semitones up is A♯.

That is why it is A♯ and not B♭: B♭ is the same key on the piano, but from E it would be a 5th, not a 4th.

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 E Lydian:

E · F♯ · G♯ · A♯ · B · C♯ · D♯

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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