C♯ Dominant 7th Chord (C#7, Db7) on Piano
The C#7 chord (C# dominant 7th) is built from 4 notes: C# – E# – G# – B. It is also written as Db7.
Play these notes on a MIDI keyboard, your computer keyboard, or the on-screen keys and ChordKeys will name the chord back to you.
Notes and intervals
| Note | Degree | Interval from C# | Semitones |
|---|---|---|---|
| C# | 1 | root | 0 |
| E# | 3 | major 3rd | 4 |
| G# | 5 | perfect 5th | 7 |
| B | b7 | minor 7th | 10 |
Inversions
Rearranging which note sits at the bottom gives you 4 playable voicings of the same chord. Inversions let you move between chords with less hand movement.
| Voicing | Notes | Bass note |
|---|---|---|
| Root position | C# – E# – G# – B | C# in the bass |
| 1st inversion | E# – G# – B – C# | E# in the bass |
| 2nd inversion | G# – B – C# – E# | G# in the bass |
| 3rd inversion | B – C# – E# – G# | B in the bass |
How the dominant 7th chord is built
Every dominant 7th chord uses the same interval formula: 1 (0 semitones), 3 (4 semitones), 5 (7 semitones), b7 (10 semitones). Starting on C# and applying that formula produces C#, E#, G#, B. Learn the formula once and you can build a dominant 7th chord on any of the twelve roots.
Keys that contain C#7
Every note of C#7 belongs to these keys, so it will sit naturally in a progression written in any of them.
Other chords on C#
Dominant 7th chords on other roots
Frequently asked questions
What notes are in a C#7 chord?
A C#7 chord contains the notes C#, E#, G#, B. Those are the 1, 3, 5, b7 degrees measured from the root note C#.
How do you play C#7 on piano?
Place your thumb on C#, then add E# and G# and B above it. With a right hand in root position the common fingering is 1–2–3–5.
Is C#7 the same as Db7?
Yes. C#7 and Db7 are enharmonic equivalents — they sound identical and use the same piano keys. Which spelling you use depends on the key you are playing in.