C# is C#, E# and G#.
It sounds plain and completely at rest. The reference every other chord on this page is a modification of.

| C# | E# | G# |
|---|---|---|
| 1 | 3 | 5 |
Tonic — the chord a progression stops on.
Also written C#maj, C#M or C# major. The same chord either way; which spelling you meet depends on who wrote the chart.
C# in root position puts C# in the bass, which is the chord as it is spelled: the note it is named after underneath everything else.
5 of C#’s 6 common shapes do this: x43121, x46664, 986669, 9-11-11-10-9-9, x-x-11-13-14-13.
Start with x43121 — no barre and down at the nut. None of the shapes for C# uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 4 of the 6 need a barre. Together they cover the neck from the 1st fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| x43121 | 1st fret | C#, root position | E# | all fretted |
| x46664 | 4th fret | C#, root position | G# | barred |
| 986669 | 6th fret | C#, root position | C# | barred |
| xx6669 | 6th fret | G#, 2nd inversion | C# | barred |
| 9-11-11-10-9-9 | 9th fret | C#, root position | C# | barred |
| x-x-11-13-14-13 | 11th fret | C#, root position | E# | all fretted |
The same notes rebuilt from scratch give 46 triad voicings, each on its own page.
How you get to it. The turn that lands on C# is D#m7 to G#7 — the ii and the V of C# — and G#7 shares its third and seventh with D#m7, so the hand barely moves between them.
In which keys. Every note of C# belongs to C# major (the I), Eb minor (the ♭VII), F minor (the ♭VI), F# major (the V), Ab major (the IV) and Bb minor (the ♭III).
Every note of C# is in C# major pentatonic, C# major, C# lydian, C# mixolydian and C# lydian dominant.
Change one note of C# and you have C#m (the major third becomes a minor third), C#sus2 (the major third becomes a ninth), C#sus4 (the major third becomes a fourth), C#maj7 (add the major seventh), C#add9 (add the ninth) or C#5 (drop the major third).
C# is a major chord — root, major third, fifth. Major chords on every root.
On C#’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.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.