What Is a Dominant 7th Chord?
A dominant 7th chord is a major triad with a minor 7th added above the root. It's the most harmonically active chord in Western music — built with two dissonant intervals that both need to resolve.
The "dominant" name comes from its role: it naturally occurs on the 5th scale degree (the dominant) of a major scale, and its powerful tension creates the strongest pull back to the tonic. Every functional harmony — from Bach to blues — uses the dominant 7th.
How to Build a Dominant 7th Chord
Formula
Root + Major 3rd + Perfect 5th + Minor 7th
Semitones: 0 — 4 — 7 — 10
Example: C Dominant 7th (C7)
- C (root)
- E (4 semitones = major third)
- G (7 semitones = perfect fifth)
- B♭ (10 semitones = minor seventh)
Why the tension? The E and B♭ form a tritone — the most dissonant interval in Western music, spanning exactly 6 semitones. This tritone wants to resolve: E moves up to F, B♭ moves down to A — arriving at an F major chord.
All 12 Dominant 7th Chords
| Chord | Root | Major 3rd | Perfect 5th | Minor 7th |
|---|---|---|---|---|
| C7 | C | E | G | B♭ |
| G7 | G | B | D | F |
| D7 | D | F# | A | C |
| A7 | A | C# | E | G |
| E7 | E | G# | B | D |
| B7 | B | D# | F# | A |
| F#7 | F# | A# | C# | E |
| F7 | F | A | C | E♭ |
| B♭7 | B♭ | D | F | A♭ |
| E♭7 | E♭ | G | B♭ | D♭ |
| A♭7 | A♭ | C | E♭ | G♭ |
| D♭7 | D♭ | F | A♭ | C♭ |
The Sound of a Dominant 7th Chord
Tense, bluesy, powerful, unresolved, gritty, driving.
The dominant 7th is the sound of tension demanding release. Play a G7 chord and every musician in the room expects C major to follow. That pull is so strong it's practically physical. It's the engine of all tonal music — the force that makes progressions move.
In blues, dominant 7th chords are used on ALL chord positions (I7, IV7, V7), which gives blues its characteristic gritty, unresolved energy. The blues doesn't fully resolve — it stays in beautiful tension throughout.
Dominant 7th in Keys
In every major key, the dominant 7th naturally occurs on the 5th scale degree:
Key of C Major: G7 → C (V7 → I resolution)
Key of G Major: D7 → G (V7 → I resolution)
Key of F Major: C7 → F (V7 → I resolution)
How to Use Dominant 7th Chords
1. As the V7 chord: Use before your I chord for powerful resolution. V7-I is the strongest cadence in music.
2. In blues: Play I7-IV7-V7 for the classic 12-bar blues structure. All three chords are dominant 7ths.
3. Secondary dominants: Apply a dominant 7th to ANY chord in your key to create temporary tension toward that chord. V7/IV, V7/V, V7/vi.
4. In jazz: The ii-V7-I is the foundation of jazz harmony. Master G7 to Cmaj7 and you understand the core of jazz.
Free: Chord Ear Training Cheat Sheet
Train your ear to hear the tension in dominant 7th chords and predict where they'll resolve.