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Chord · Reference entry
F♯ 7♭9♯11
7♭9♯11 · F♯ – A♯ – C♯ – E – G – B♯ · intervals P1-M3-P5-m7-m9-A11
The F♯ 7♭9♯11 chord (F♯7♭9♯11) contains the notes F♯, A♯, C♯, E, G, and B♯. Its interval formula is R-M3-P5-m7-m9-A11. A dominant 7th with a flatted 9th and raised 11th — densely altered, used as a tritone sub in jazz.
=G♭ 7♭9♯11›
This is the same chord as G♭ 7♭9♯11 — the same keys on the keyboard, spelled with flats.
Maintained for accuracy · Last updated July 2026 · How we review
Flashcards · Chord
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F♯7♭9♯11
The F♯ 7♭9♯11 chord is a six-note chord made up of F♯, A♯, C♯, E, G, and B♯. It is built from a root, major third, perfect fifth, minor seventh, minor ninth, and augmented eleventh.
Construction
F♯ 7♭9♯11 = Root + Major 3rd + Perfect 5th + Minor 7th + Minor 2nd + Diminished 5th = F♯ · A♯ · C♯ · E · G · B♯
Note
Interval
Degree
F♯
Root
1
A♯
Major 3rd
3
C♯
Perfect 5th
5
E
Minor 7th
♭7
G
Minor 2nd
♭9
B♯
Diminished 5th
♭5
Key Signature
A chord has no key signature of its own, but the F♯ 7♭9♯11 is the tonic (I) chord of F# Major, whose key signature has 6 sharps (F♯, C♯, G♯, D♯, A♯, E♯).
F♯C♯G♯D♯A♯E♯
Order of sharps
Sharps are added to a key signature in a fixed order. Each new sharp key adds the next sharp on the list.
F♯C♯G♯D♯A♯E♯B♯
Mnemonic:Father Charles Goes Down And Ends Battle
Chords in the Key of F♯ Major
These are the triads built on each degree of the F♯ major scale:
The notes F♯ – A♯ – C♯ – E – G – B♯ aren’t exclusive to this chord. Depending on which note is the bass and how the chord functions, the same pitches also spell:
Keep going with the 7♭9♯11 chord — these pages cover the underlying theory, the connected reference material, and the practice tools that work with this chord.
The note names, intervals, fingering, and harmony on this chord page are grounded in the following sources. Public domain treatises and scores are linked to their full text; primary data is piano.org's own interval-derived reference dataset — continuously maintained and human-verified, with no fixed publication date.