C♯ Major
Key Signature
| Property | Value |
|---|---|
| Tonic | C♯ |
| Mode | Major |
| Accidentals | 7 sharps |
| Key Signature Notes | F♯, C♯, G♯, D♯, A♯, E♯, B♯ |
C♯ major has seven sharps and is enharmonically equivalent to D♭ major. It is rarely used in practice but appears in some pieces where sharp notation is preferred throughout.
Diatonic Chords
The seven diatonic chords of C♯ Major — each built on a scale degree using only the notes of the key signature:
| Degree | Roman Numeral | Chord Type | Chord |
|---|---|---|---|
| 1 | I | Major | C♯ Major |
| 2 | ii | Minor | D♯ Minor |
| 3 | iii | Minor | E♯ Minor |
| 4 | IV | Major | F♯ Major |
| 5 | V | Major | G♯ Major |
| 6 | vi | Minor | A♯ Minor |
| 7 | vii° | Diminished | B♯ Diminished |
Related Keys
- Relative Minor
- A Sharp Minor — shares the same key signature.
- Parallel Minor
- C Sharp Minor — same tonic, different key signature.
See all key relationships on the Circle of Fifths.
Scales in C♯ Major
Common scales built from the C♯ tonic:
Transposing Instrument Context
Sharp-key signatures like C♯ Major are comfortable for open-string instruments (guitar, violin). B♭ instruments (trumpet, clarinet, tenor saxophone) read in D♯ major to sound C♯ Major. E♭ instruments (alto saxophone, E♭ clarinet) read in A♯ major to sound C♯ Major. Standard guitar tuning (E A D G B E) resonates naturally in C♯ Major.