C7♭13♯9

6-note dominant flat 13 sharp 9 on CC, D♯, E, G, G♯, A♯.

Press to hear the chord strummed low to high.

A dominant seventh with a sharp ninth and a flat thirteenth — two of the altered tensions at once, jagged and blues-tinged.

The notes

Pitches taken from the first fingering below — click any note to open its frequency page.

Interval formula

DegreeNoteWhat it is
1Croot
♯9D♯sharp ninth
3Emajor third
5Gperfect fifth
♭13G♯flat thirteenth
♭7A♯flat seventh (dominant)

The formula reads in semitones above the root (C): 1, ♯9, 3, 5, ♭13, ♭7. A voicing may leave a tone out — often the fifth — but never adds one from outside this set.

Ukulele fingerings · 4

132
open position
3fr1234
from fret 3
6fr4311
from fret 6
6fr3412
from fret 6

Read a diagram top-down: the thick bar is the nut, dots are where to press (the number is which finger), means play the open string, means don't play it. A bar across strings is a barre.

Other C chords

7♭13♯9 chords on every root