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Chord · Reference entry

C 9♯11

9♯11 · C – D – E – F♯ – G – B♭

chord·/chords/dominant-9th-sharp-11th/c/

The C 9♯11 chord contains the notes C, D, E, F♯, G, and B♭.

Notes: C, D, E, F♯, G, B♭ · Piano keys: C D E F♯ G B♭

By Justin Evans · Pianist
Maintained for accuracy · Last updated July 2026 · How we review

At the keyboard

C · D · E · F# · G · Bb
Flashcards · Chord
Three questions on C 9♯11
Answer on the keyboard, not with buttons. No login required.
C

The C 9♯11 chord is a six-note chord made up of C, D, E, F♯, G, and B♭.

Construction

C 9♯11 = Root + Major 2nd + Major 3rd + Diminished 5th + Perfect 5th + Minor 7th = C · D · E · F♯ · G · B♭
NoteIntervalDegree
CRoot1
DMajor 2nd9
EMajor 3rd3
F♯Diminished 5th♭5
GPerfect 5th5
B♭Minor 7th♭7

Key Signature

A chord has no key signature of its own, but the C 9♯11 is the tonic (I) chord of C Major, whose key signature has no sharps or flats.

Chords in the Key of C Major

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

C1C2C3CEGC5C6C7C8
I — C Major (major)
DegreeNumeralChordQuality
1IC MajorMajor
2iiD MinorMinor
3iiiE MinorMinor
4IVF MajorMajor
5VG MajorMajor
6viA MinorMinor
7vii°B DiminishedDiminished

C 9♯11 — Frequently Asked Questions

What is the C 9♯11 chord on piano?
The C 9♯11 chord contains the notes C – D – E – F♯ – G – B♭. On piano, play these notes together to sound the chord.

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(1799)

    Piano Sonata No. 8 in C minor, Op. 13 ("Pathétique")

    Public domain score
  4. 4

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Entry reviewed and maintained by Justin Evans. Corrections are read and applied.Report an error

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