Dominant Seventh Chords Explained

Why the dominant 7th wants to resolve

Inside every dominant seventh chord hides a tritone, the interval between its major third and its flat seventh. In G7 that is B and F, three whole tones apart, the most unstable interval in tonal music. Your ear hears it as a question, and the answer is the chord a fifth below: the B in G7 rises to C, the F falls to E, and G7 melts into C major. That collapse is the single most important motion in Western harmony, the V to I cadence, and the dominant 7th is what powers it.

That is also why it sounds bluesy on its own. Hold a C7 and it never feels finished, it leans forward. Blues leans into that tension on purpose, using dominant 7ths where classical music would resolve them, which is why a twelve-bar blues can be three dominant 7ths and nothing else and still sound complete.

Build any dominant 7th chord

Pick a root and see the four notes light up: root, major 3rd, 5th and flat 7th. The keyboard shows the notes of the chord, in any octave.

The formula, and a few to know first

Every dominant 7th is built the same way: take the major triad and add the note a whole step below the root's octave, the flat seventh. Learn the formula once and all 12 follow. Start with the three that show up everywhere:

• G7 = G B D F. The classic V of C major; it pulls straight home to C.
• C7 = C E G Bb. The heart of a blues in F, and the V of F major.
• D7 = D Gb A C. A bright, common dominant; the V of G. (The game spells the major third as Gb by its flat convention; on a lead sheet you will often see it written F#.)

Once those feel automatic, use the builder above to walk the rest. The fastest way to lock them in is to play them and be corrected on the spot, which is exactly what chord training in the game does.

Where you actually hear dominant 7ths

Everywhere a progression needs momentum. In blues, the I, IV and V are all dominant 7ths. In jazz, the ii-V-I turnaround runs on the dominant in the middle, and altered dominants pile tension on top of it. In pop and soul, a well-placed 7th is what turns a plain major chord into something that leans into the next bar. Training your ear to spot that leaning quality is a skill in itself, and pairs naturally with chord recognition practice.

Practise dominant 7ths in the game

Open the game and build a Custom pool of dominant 7th chords across all 12 roots, or start on Standard Levels and add 7ths as you climb. Play each one on your MIDI keyboard or into your microphone; the game tells you immediately whether the shape was right, and the tempo rises so recall has to become automatic. The chords you keep missing are your practice list for tomorrow. Free in the browser, nothing to install.

Common questions

What is a dominant seventh chord?

A dominant seventh chord is a major triad with a flat seventh added on top: root, major third, perfect fifth and minor seventh. In C that is C, E, G and Bb. The clash between the major third and the flat seventh gives it a restless, bluesy pull that wants to resolve.

How is a dominant 7th different from a major 7th?

The seventh. A dominant 7th uses a flat (minor) seventh, so C7 is C E G Bb and sounds tense and bluesy. A major 7th uses the natural seventh, so Cmaj7 is C E G B and sounds smooth and dreamy. One note apart, completely different mood.

Why does a dominant 7th want to resolve?

It contains a tritone between its third and flat seventh, an unstable interval the ear wants resolved. That is why G7 pulls so strongly to C: the tritone in G7 collapses inward to the notes of C major. It is the engine behind most cadences in Western music.

How do I practise all 12 dominant 7th chords?

Drill them one at a time, then mixed, with instant feedback. In ChordRunner you can build a Custom pool of dominant 7th chords across all 12 roots and play them on a MIDI keyboard or through your microphone, getting told immediately whether each shape was right.