Chords
Dominant seventh chord
A dominant seventh chord is a major triad with a minor seventh on top (1 3 5 ♭7), such as G7 = G B D F, and it pulls strongly toward the tonic.
What is a dominant seventh chord?
It is the seventh chord that forms naturally on the 5th degree of a major scale, the dominant. Its formula is 1 3 5 ♭7: a major triad plus a minor seventh. In C major the 5th degree is G, so G7 = G B D F.
It is written with a plain "7": G7, E7, A7. No other chord in the major scale combines a major third with a minor seventh, which is what makes it unique.
Why does a dominant seventh want to resolve?
Between its third and its seventh lies a tritone: B and F in G7. That unstable interval resolves by contrary motion, one semitone each: B rises to C, F falls to E. You land on C and E, the heart of the C chord.
On guitar, isolate those two notes on strings 4 and 3: F at the 3rd fret and B at the 4th, then E at the 2nd fret and C at the 5th. Each finger moves one fret, and you hear the whole V-I cadence with just two notes.
How do you play dominant seventh chords on guitar?
Open shapes, from low E to high E:
| Chord | Shape | Notes |
|---|---|---|
| E7 | 020100 | E B D G♯ B E |
| A7 | x02020 | A E G C♯ E |
| D7 | xx0212 | D A C F♯ |
| G7 | 320001 | G B D G B F |
| C7 | x32310 | C E B♭ C E |
| B7 | x21202 | B D♯ A B F♯ |
Movable barre shapes: E shape with the root on the 6th string, G7 = 353433; A shape on the 5th string, C7 = x35353.
Where is the dominant seventh chord used?
- V7-I cadence: G7 to C, D7 to G, E7 to Am.
- The jazz ii-V-I: Dm7, G7, Cmaj7.
- Secondary dominants: A7 going to Dm in the key of C is a secondary dominant (V7 of ii). Likewise E7 to Am, D7 to G.
- The blues: all three chords are 7 chords (A7, D7, E7 in A), with no need to resolve.
- Tritone substitution: D♭7 can replace G7 because both share the same tritone (F and C♭ = B). The chord substitutions tool shows these substitutions with playable voicings.
For even more tension, add ♭9, ♯9, ♯5 or ♭5: that gives you the altered dominant.
Key takeaways
- Formula: 1 3 5 ♭7, written "7" (G7 = G B D F).
- It is built on the 5th degree of the major scale.
- Its tritone (3 and ♭7) resolves by semitones into the tonic chord.
- Core shapes: E7
020100, A7x02020, G7320001, barre G7353433.
Frequently asked questions
What is the difference between G7 and Gmaj7?
The seventh: G7 has F (minor seventh), Gmaj7 has F♯ (major seventh). G7 is tense and pulls toward C, while Gmaj7 is stable and smooth. On a chord chart, a plain "7" always means a dominant seventh.
What scale do you play over a dominant seventh chord?
The Mixolydian mode of the root: over G7, G A B C D E F, which is the C major scale played from G. In the blues, the minor pentatonic (G B♭ C D F) also works, because its ♭3 rubs deliberately against the major third.
Why is it called a "dominant" seventh?
Because it is built on the dominant, the 5th degree of the key. By extension, any 7 chord that resolves down a fifth is called a dominant chord, even outside the home key.
Related terms
Practise in the workshop
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