Chord · C Dominant 9th
C9 Chord
C9 is C, E, G, Bb and D — funky, soulful; James Brown territory.
C9 on every instrument
The same 5 notes, 4 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.
What C9 is made of
C9 (C ninth) is built from the notes C, E, G, Bb, D, with the interval pattern 1, 3, 5, b7, 9.
Stack 1, 3, 5, b7 and 9 on a root of C and you get C, E, G, Bb and D. That interval recipe is what makes the chord a ninth chord — move the same shape to another root and the character travels with it, which is why D9 sounds like a transposed C9.
Dominant 9th: Funky, soulful; James Brown territory.
Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with B♭ rather than its enharmonic equivalent.
Keys that contain C9
All 5 notes sit inside the scale of 2 keys. The roman numeral marks the degree the chord is rooted on.
Major keys
Minor keys
Other chords on C
Same root, different colour.
The same ninth shape, moved
The identical interval recipe, built on other roots.
Questions people ask about C9
- What notes are in the C9 chord?
- C9 is made of C, E, G, Bb and D — the 1, 3, 5, b7 and 9 degrees of a ninth chord built on C.
- What keys use the C9 chord?
- Every note of C9 belongs to 2 keys: F Major (V), D Minor (VII). The roman numeral is the scale degree the chord is rooted on.
- How do you play C9 on guitar and piano?
- This page shows C9 on guitar, piano, ukulele and mandolin — 8 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.
Learn the theory behind it
Why C9 behaves the way it does — the guides that explain the chord instead of just spelling it.