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Chord · Reference entry

C♯ 7♯9♯11

7♯9♯11 · C♯ – E♯ – G♯ – B – D♯♯ – F♯♯ · intervals P1-M3-P5-m7-A9-A11

The C♯ 7♯9♯11 chord (C♯7♯9♯11) contains the notes C♯, E♯, G♯, B, D♯♯, and F♯♯. Its interval formula is R-M3-P5-m7-A9-A11. A dominant 7th with raised 9th AND raised 11th — maximally tense, the late-Coltrane altered sound.

D♭ 7♯9♯11
This is the same chord as D♭ 7♯9♯11 — the same keys on the keyboard, spelled with flats.

At the keyboard

C# · E# · G# · B · D## · F##
Maintained by Justin Evans, a pianist of 25 years
Maintained for accuracy · Last updated July 2026 · How we review
Flashcards · Chord
Three questions on C♯ 7♯9♯11
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C♯7♯9♯11

The C♯ 7♯9♯11 chord is a six-note chord made up of C♯, E♯, G♯, B, D♯♯, and F♯♯. It is built from a root, major third, perfect fifth, minor seventh, augmented ninth, and augmented eleventh.

Construction

C♯ 7♯9♯11 = Root + Major 3rd + Perfect 5th + Minor 7th + Minor 3rd + Diminished 5th = C♯ · E♯ · G♯ · B · D♯♯ · F♯♯
NoteIntervalDegree
C♯Root1
E♯Major 3rd3
G♯Perfect 5th5
BMinor 7th♭7
D♯♯Minor 3rd♭3
F♯♯Diminished 5th♭5

Key Signature

A chord has no key signature of its own, but the C♯ 7♯9♯11 is the tonic (I) chord of C# Major, whose key signature has 7 sharps (F♯, C♯, G♯, D♯, A♯, E♯, B♯).

F♯C♯G♯D♯A♯E♯B♯

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 C♯ Major

These are the triads built on each degree of the C♯ major scale:

C1C2C3C4E♯C5C6C7C8C♯G♯
I — C♯ Major (major)
DegreeNumeralChordQuality
1IC♯ MajorMajor
2iiD♯ MinorMinor
3iiiF MinorMinor
4IVF♯ MajorMajor
5VG♯ MajorMajor
6viA♯ MinorMinor
7vii°C DiminishedDiminished

C♯ 7♯9♯11 — Frequently Asked Questions

What is the C♯ 7♯9♯11 chord on piano?
The C♯ 7♯9♯11 chord contains the notes C♯ – E♯ – G♯ – B – D♯♯ – F♯♯. On piano, play these notes together to sound the chord.
What notes are in the C# 7♯9♯11 chord?
The C# 7♯9♯11 chord (C#7♯9♯11) contains 6 notes: C#, F, G#, B, E, G. Formula: R-M3-P5-m7-A9-A11.
How is C#7♯9♯11 used in music?
C#7♯9♯11 is used in jazz, fusion, and contemporary music to add harmonic color. It appears as a dominant or tonic chord depending on context.
What is the scale degree formula for C#7♯9♯11?
C#7♯9♯11 uses scale degrees 1-3-5-b7-#9-#11, giving it its distinctive sound.

Related Tools

Chord FinderLook up any chord — see the notes, hear it, and play along.Chord DrillTimed drills to build speed and recognition across all chord types.Practice RoomPlug in a MIDI keyboard and get real-time feedback on every chord and scale.Circle of FifthsVisualize key relationships, relative minors, and key signatures.MIDI MonitorLive MIDI message stream with note names, velocity, and a scrolling staff.

References & Further Reading

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.

  1. 1

    Prout, Ebenezer(1889)

    Harmony: Its Theory and Practice

    Public domain treatise
  2. 2

    Goetschius, Percy(1889)

    The Material Used in Musical Composition

    Public domain treatise
  3. 3

    Beethoven, Ludwig van(1802)

    Piano Sonata No. 14 in C♯ minor, Op. 27 No. 2 ("Moonlight"), i

    Public domain score
  4. 4

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