Scale degrees · E major

The ♯9 of E is F𝄪

The ♯9 (sharp nine, written #9) of E is F𝄪 (F double sharp): an augmented ninth above the root.

E — the root, 1F𝄪 — the ♯9

How to find it

A 9th is a 2nd an octave up, so it takes the 2nd's letter: E, F.

Then the sound: an augmented ninth is 15 semitones above E, and the F that is 15 semitones up is F𝄪.

That is why it is F𝄪 and not G: G is the same key on the piano, but from E it would be a 10th, not a 9th.

Where you meet it

The ♯9 is the tension of the 7♯9 chord. It sounds like the minor 3rd, but it is a raised 9th and is spelled with the 9th's letter.

In E7♯9:

E · G♯ · B · D · F𝄪

The ♯9 in every key

KeyThe ♯9
CD♯
GA♯
DE♯
AB♯
EF𝄪
BC𝄪
F♯G𝄪
D♭E
A♭B
E♭F♯
B♭C♯
FG♯

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