A close-position chord with the second voice from the top lowered an octave. Sits on four adjacent strings.
Caug7 is C, E, G# and Bb — C7 with the fifth raised a semitone.
It sounds strained and chromatic. The raised fifth is heard as a ♭13 sitting a semitone above where it is going, so the chord pushes harder than a plain dominant.

| C | E | G# | Bb |
|---|---|---|---|
| 1 | 3 | ♯5 | ♭7 |
Altered dominant — the pull of a 7, sharpened.
Also written C7#5, C+7 or C7(#5). The same chord either way; which spelling you meet depends on who wrote the chart.
Take the four notes stacked as close together as they go, then drop the second voice from the top an octave. The gap it opens is what makes the chord sound like a chord rather than a cluster.
It lands on four adjacent strings, which is why it is the workhorse voicing on guitar.
Caug7 has 13 of them, on the middle four strings, the bottom four strings and the top four strings, from open position up to the 13th — every inversion the chord has: C in the bass, E in the bass, G# in the bass and Bb in the bass. The one to learn first is the Bb shape at the nut, which is the easiest grip here.
5 of them sit on the middle four strings, so you can run the inversions up one set without changing strings — which is the whole reason to learn them as a family rather than as separate grips.
Start with x323x4 — down at the nut. None of the shapes for Caug7 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. None of them needs a barre. Together they cover the neck from the 2nd fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x323x4 | 2nd fret | C, root position | G# | all fretted |
| x36354 | 3rd fret | C, root position | G# | all fretted |
| 8x8990 | 8th fret | C, root position | G# | 1 open string |
| 878x9x | 7th fret | C, root position | G# | all fretted |
| x-x-10-13-11-12 | 10th fret | C, root position | E | all fretted |
The same notes rebuilt from scratch give 2 shell, 9 drop 3 and 1 open string voicings, each on its own page.
Tensions. A shell of Caug7, root, third and seventh, leaves a string free, and the tones that belong over it are the b9 (Db), the 9 (D), the #9 (D#) and the #11 (F#).
Caug7 is a dominant with its tension raised, so it still points at F — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.
Voice by voice, Caug7 → F. 3 voices move by a semitone, and one note is common to both chords.
| In Caug7 | Moves | In F |
|---|---|---|
| C, the root | stays where it is | C, the fifth |
| E, the major third | rises a semitone | F, the root |
| G#, the sharp fifth | rises a semitone | A, the major third |
| Bb, the flat seventh | falls a semitone | A, the major third |
Every note of Caug7 is in C whole tone and C altered.
Change one note of Caug7 and you have Cmaj7#5 (the flat seventh becomes a major seventh), C7 (the sharp fifth becomes a fifth), C7/G (the sharp fifth becomes a fifth), C7b5 (the sharp fifth becomes a flat fifth), Calt (add the flat ninth) or Caug (drop the flat seventh).
Caug7 is an altered chord — a dominant seventh with its fifth or ninth moved. Altered dominant chords on every root.
On Caug7’s sound and use this page follows Mark Levine, The Jazz Theory Book (Sher Music, 1995). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.