Chord reference · four-note chord
C#dim7 chord (C-sharp diminished seventh)
The C#dim7 chord contains 4 written tones: C♯, E, G, B♭. Its interval formula is 1–♭3–♭5–♭♭7.
C#dim7 chord notes and interval formula
The formula 1–♭3–♭5–♭♭7 means the chord is measured from C♯ using the root, minor third, diminished fifth, and diminished seventh. In semitone numbers from the root, the pattern is 0–3–6–9.
| Degree | Interval | Semitones | Note |
|---|---|---|---|
| 1 | Root | 0 | C♯ |
| ♭3 | Minor Third | 3 | E |
| ♭5 | Diminished Fifth | 6 | G |
| ♭♭7 | Diminished Seventh | 9 | B♭ |
How to play C#dim7 on piano
Start with the notes in root position from low to high: C♯ – E – G – B♭. Right hand 1–2–3–5; left hand 5–3–2–1 is a useful starting point, but black-key combinations and melodic movement may make another fingering more comfortable.
For a cleaner accompaniment, place the root in the left hand and play the remaining tones in the right. With extended chords, keep the third and seventh because they identify the chord quality most clearly.
How to play C#dim7 on guitar
Try the shape x-4-5-3-5-0 in standard tuning, read from low E to high E. The sounding-string details are: E mute; A fret 4: C♯; D fret 5: G; G fret 3: B♭; B fret 5: E; E open: E. Keep every note clear and release pressure from strings marked “x.”
This is one voicing, not the only correct shape. The chord remains C#dim7 whenever the essential pitch classes are present; doubling, omission, and bass-note choice change the voicing rather than the basic chord name.
C#dim7 inversions and slash chords
Inversions keep the same notes but place a different chord tone in the bass. They are useful for smoother bass lines, compact keyboard movement, and alternative guitar voicings.
| Position | Symbol | Notes low to high | Bass |
|---|---|---|---|
| Root position | C#dim7 | C♯ – E – G – B♭ | C♯ |
| 1st inversion | C#dim7/E | E – G – B♭ – C♯ | E |
| 2nd inversion | C#dim7/G | G – B♭ – C♯ – E | G |
| 3rd inversion | C#dim7/Bb | B♭ – C♯ – E – G | B♭ |
What C#dim7 sounds like and where it fits
The C-sharp diminished seventh chord is symmetrical and highly tense. The diminished seventh chord is built from stacked minor thirds. Its symmetry makes several enharmonic spellings possible and lets the chord resolve convincingly in multiple directions. A common voice-leading move resolves the root C♯ upward to D.
C#dim7 compared with similar chords
Small interval changes create different chord names. Use this table to avoid confusing C#dim7 with nearby structures.
| Chord | Quality | Formula | Notes |
|---|---|---|---|
| C#dim | Diminished | 1–♭3–♭5 | C♯, E, G |
| C#m7b5 | Half-Diminished Seventh | 1–♭3–♭5–♭7 | C♯, E, G, B |
Frequently asked questions
What notes are in the C#dim7 chord?
The C#dim7 chord contains C♯, E, G, B♭. Its interval formula is 1–♭3–♭5–♭♭7.
How do you play C#dim7 on piano?
Play C♯, E, G, B♭ together. A practical root-position fingering is right hand 1–2–3–5; left hand 5–3–2–1; adjust the fingering to your hand and musical context.
How do you play C#dim7 on guitar?
One compact standard-tuning shape is x-4-5-3-5-0 from the low E string to the high E string. An “x” means mute that string.
What does the symbol C#dim7 mean?
The root is C♯. The suffix dim7 identifies a diminished seventh structure with the formula 1–♭3–♭5–♭♭7.
How many inversions does C#dim7 have?
A 4-note chord has 4 closed-position arrangements when every chord tone is retained: root position plus 3 inversions. Extended practical voicings may omit notes.