C#7 guitar chord
An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful.
- Tap a note to hear it
- Arrows change position
- Fingers, notes or intervals
- Play the chord
About C#7 — open string voicings
C#7 is C#, E#, G# and B — C# with the flat seventh added on top.
It sounds restless and pointed at something. The third and the flat seventh are a tritone apart and each moves by a semitone into the next chord; that is the engine of a cadence, and the whole vocabulary of the blues.
C#7 notes and formula
| C# | E# | G# | B |
|---|---|---|---|
| 1 | 3 | 5 | ♭7 |
Dominant — it points a fifth down.
Also written C#dom7 or C# dominant 7. The same chord either way; which spelling you meet depends on who wrote the chart.
How to play C#7
An open string left ringing against a fretted grip. It costs no finger, so it can sound a note the closed shape has none left for: a tension on top, or a pedal root underneath.
These belong to their key rather than to a shape: they cannot be moved up the neck. D, A, G and E have many; E♭ has a handful.
C#7 has 6 of them, on strings 5-4-3-2-1, strings 6-5-4-3-2-1 and strings 6-4-3-2-1, from the 2nd fret up to the 6th — every inversion the chord has: C# in the bass, G# in the bass and B in the bass. The one to learn first is the G# shape at the 3rd fret, which is the easiest grip here.
3 of them sit on strings 6-4-3-2-1, 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 x4342x — no barre and down at the nut. None of the shapes for C#7 uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. 4 of the 6 need a barre. Together they cover the neck from the 2nd fret to the 13th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x4342x | 2nd fret | C#, root position | C# | all fretted |
| x46464 | 4th fret | C#, root position | G# | barred |
| xx6667 | 6th fret | G#, 2nd inversion | B | barred |
| 986667 | 6th fret | C#, root position | B | barred |
| 9-11-9-10-9-9 | 9th fret | C#, root position | C# | barred |
| x-x-11-13-12-13 | 11th fret | C#, root position | E# | all fretted |
The same notes rebuilt from scratch give 4 shell, 13 drop 2 and 9 drop 3 voicings, each on its own page.
Tensions. A shell of C#7, root, third and seventh, leaves a string free, and the tones that belong over it are the b9 (D), the 9 (D#), the #9 (D##), the #11 (F##), the b13 (A) and the 13 (A#).
How to use C#7
C#7 is the V of F#, and that is where it goes if it goes anywhere: the third and the flat seventh are a tritone apart, and both resolve by a semitone into F#.
Voice by voice, C#7 → F#. 2 voices move by a semitone, and one note is common to both chords.
| In C#7 | 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 fifth | falls a whole tone | F#, the root |
| B, the flat seventh | falls a semitone | A#, the major third |
In which keys. Every note of C#7 belongs to Eb minor (the ♭VII) and F# major (the V, the dominant).
What to play over C#7
Every note of C#7 is in C# mixolydian, C# lydian dominant and C# half-whole diminished.
Chords near C#7
Change one note of C#7 and you have C# (drop the flat seventh), C#maj7 (the flat seventh becomes a major seventh), C#m7 (the major third becomes a minor third), C#add9 (the flat seventh becomes a ninth), C#6 (the flat seventh becomes a sixth) or C#7sus4 (the major third becomes a fourth).
C#7 is a dominant chord — root, major third, fifth, minor seventh. Dominant seventh chords on every root.
On C#7’s sound and use this page follows Edward Aldwell & Carl Schachter, Harmony and Voice Leading (Schirmer / Cengage, 4th ed., 2011). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.