C#13 Chord on Guitar
C#13 = C# – F – G# – B – D# – A# (Root, Major 3rd, Perfect 5th, Minor 7th, Major 9th, Major 13th)
C#13 is the dominant family's fullest extension, theoretically climbing all the way through the thirteenth degree, but no six-string chord voices every one of those tones at once. Fingered at the ninth fret, this shape keeps root, third, flat seventh, and thirteenth — the same practical compromise every guitarist relying on 13th chords makes, regardless of root.
The formula runs C#, F, G#, B, D#, A#, but the ninth and eleventh drop out of the actual voicing, leaving four notes to do the real work: root and third establish the major-dominant identity, the flat seventh supplies the pull toward resolution, and the thirteenth — really a major sixth voiced an octave higher — adds the rich, jazz-club color riding on top. It's a noticeably more sophisticated sound than a plain C#7, the kind of chord that shows up right before a cadence in more polished jazz comping rather than in a simple blues turnaround.
Fingerings
Barre (9th fret)
How to Practice It
The thirteenth sits an octave above where a plain sixth would land on a simpler chord, so getting that top note to ring cleanly matters more than any other single note in this voicing — a muted or buzzed top string quietly turns a rich 13th chord back into a plain dominant seventh, and it's easy not to notice why the sound suddenly feels flatter. Practicing the shift from a bare C#7 into this fuller C#13 shape and back isolates exactly which finger carries that top color and why it matters.
Common Progressions
- D#m7 – G#7 – C#13 (ii7 – V7 – I13, a jazz turnaround landing on a rich tonic)
- C#13 – F# (V13 – I, the fullest possible dominant pull)
- C#13 – C#7 – F#6 (moving from rich color down to a simpler resolution)
- G#13 – C#13 – F#13 (a progression stacking 13th chords throughout)
FAQ
- Does the C#13 voicing actually include all six notes of its theoretical formula?
- No — the full stack runs through the ninth and eleventh as well, but a practical guitar voicing keeps only root, third, flat seventh, and thirteenth, since cramming every extension onto six strings isn't possible or musically useful.
- What does the thirteenth contribute to the sound?
- It's the same pitch class as a major sixth, just voiced an octave higher, and it's the note most responsible for the chord's rich, sophisticated color — without it, C#13 collapses into a plainer-sounding C#7.
- Why isn't the ninth part of this voicing?
- With only six strings and four notes already prioritized, the ninth is the extension least essential to the chord's core dominant identity, so it's the one left out in practice.
- Is C#13 noticeably harder to play than C#9 at this position?
- Not really in terms of raw coordination, since both need a held barre with a couple of extra fingers added on top; what makes C#13 feel trickier is that its single top note is doing more work to establish the chord's color than any one note in the leaner C#9 shape.
- Where does C#13 typically show up in a chart?
- Almost always right before a resolution to F#, functioning as an especially rich-sounding dominant that jazz writing often substitutes for a plain seventh at exactly this kind of cadence point.
- Can a 13th chord substitute for a plain dominant seventh elsewhere in a progression?
- In most jazz contexts, yes — the added color decorates the chord without altering its underlying dominant function, so a 13th chord can generally stand in wherever a plain seventh was already resolving normally.
- Is there a way to hear the thirteenth's contribution in isolation?
- Playing just the barre plus the top string alone, without the middle notes, isolates root and thirteenth together, which is a quick way to hear that sixth-like color before adding the rest of the chord back in.
Related: how chords are built, chord finder.