A dominant 7th chord is a four-note chord built from a root, a major 3rd, a perfect 5th and a minor 7th. A G7 chord is G, B, D and F: the major triad G–B–D plus the minor 7th F, ten semitones above the root, which creates the tension that makes the chord want to resolve.
What is a dominant 7th chord?
A dominant 7th chord, written with a plain 7 after the root, such as G7 or C7, is the most important four-note chord in Western music. It is a major triad with one extra note: a minor 7th, ten semitones above the root. That extra note is what gives the chord its restless, forward-leaning character. A plain major triad sounds finished and settled, but a dominant 7th sounds as if it is leaning toward something, and the ear expects it to resolve, usually to the chord a perfect 5th below its root. The name comes from the chord's home: in any major key, the dominant 7th is the chord built on the 5th degree, the dominant. In C major the dominant is G, so G7 is the dominant 7th of the key, and it pulls strongly back to C major. This pull is the engine of the V–I cadence, the most common chord movement in music, and it is also the reason the 12-bar blues is built almost entirely from dominant 7th chords: the tension never fully settles, which keeps the music moving forward.
How a dominant 7th chord is built
Build the major triad first, then add the note ten semitones above the root. For G7: G major is G, B and D, and ten semitones above G is F, so G7 is G, B, D and F. For C7: C major is C, E and G, and ten semitones above C is Bb (spelled A# in ChordFlow's sharp-only system), so C7 is C, E, G and A#. For D7: D major is D, F# and A, and ten semitones above D is C, so D7 is D, F#, A and C. The tension in the chord comes from an interval hidden inside it: the tritone between the major 3rd and the minor 7th. In G7 the 3rd is B and the 7th is F, and B to F is six semitones, a tritone, the most unstable interval in music. When G7 resolves to C major, the B rises a semitone to C and the F falls a semitone to E, and both notes land on chord tones of C major. That double semitone movement is the resolution you hear, and it is why the dominant 7th feels so satisfying when it finally arrives home. The G7 guitar chord and the C7 guitar chord show the shapes, and the key of C major shows where G7 belongs.
Worked example — A7. A major is A, C# and E. Ten semitones above A is G, so A7 is A, C#, E and G. Check the tritone: C# to G is six semitones. A7 is the dominant 7th of D major, so it resolves naturally to the D major guitar chord, where C# rises to D and G falls to F#. Try the V–I movement A7 to D on your instrument and listen for the two notes pulling in opposite directions. The chord finder and the chord progression builder both build dominant 7th chords from any root.
How to practise dominant 7th chords
Practise dominant 7ths as resolutions, not as isolated shapes, because their whole point is the movement they create. A few minutes a day on V–I pairs builds the habit.
- Play G7 to C, C7 to F and D7 to G, holding each dominant 7th for a bar and listening for the pull toward the next chord.
- On guitar, learn the open G7 guitar chord and the open C7 guitar chord, then move between them and the major chords they resolve to.
- On piano, play a dominant 7th with your right hand and the root with your left, then resolve both hands to the tonic chord a 5th below.
- Play the 12-bar blues progression in C major slowly, noticing that every chord is a dominant 7th and the tension never fully disappears.
- Use the interval calculator to check the minor 7th above any root before you build the chord.
Common mistakes
- Adding a major 7th instead of a minor 7th — A dominant 7th needs a minor 7th, ten semitones above the root. Adding a major 7th, eleven semitones, gives a major 7th chord, which sounds smooth and settled instead of tense and pulling.
- Resolving a dominant 7th to the wrong chord — A dominant 7th normally resolves down a perfect 5th to its tonic: G7 to C, D7 to G. Resolving it anywhere else is possible, but it throws away the tension the chord was built to create.
- Leaving out the 3rd — In a dominant 7th the 3rd is essential because it forms the tritone with the 7th. You can leave out the 5th and the chord still works, but without the 3rd it loses both its major quality and its pull.
Quick reference
For example, the dominant 7th chord chord on C is C – E – G – A#, and every other row follows the same pattern. The table below works out the dominant 7th chord chord on six roots so you do not have to. Read down the notes column and notice how the root, major 3rd, perfect 5th and minor 7th spacing never changes, even though the letter names do, and use the first row as the worked example you can check your own calculations against.
| Root | Dominant 7Th Chord notes |
|---|---|
| C | C – E – G – A# |
| G | G – B – D – F |
| D | D – F# – A – C |
| A | A – C# – E – G |
| E | E – G# – B – D |
| F | F – A – C – D# |
Once the six rows feel familiar, transpose the table yourself: pick a root that is not listed, work out the notes of the dominant 7th chord chord from the interval pattern, and play the result. That single exercise, repeated for a few roots, is what turns a table you have read into a skill you own.
Frequently asked questions
What notes are in a dominant 7th chord?
The root, the major 3rd, the perfect 5th and the minor 7th. G7 is G, B, D and F. The minor 7th sits ten semitones above the root, one semitone below the major 7th, and that single semitone is what makes the chord dominant rather than major.
Why is it called a dominant 7th?
Because it is the 7th chord built on the dominant, the 5th degree, of a major key. In C major the dominant is G, so G7 is the dominant 7th of the key. The name describes where the chord comes from, not just how it sounds.
What is the difference between a 7th chord and a dominant 7th?
A dominant 7th is one specific type of 7th chord: major triad plus minor 7th. Other 7th chords include the major 7th (major triad plus major 7th) and the minor 7th (minor triad plus minor 7th). When a chord symbol says just 7, as in G7, it always means dominant 7th.
Where are dominant 7th chords used?
Everywhere a chord needs to create forward motion: the V–I cadence at the end of phrases, the 12-bar blues, jazz standards, rock turnarounds and classical music. Any time music needs to move home, a dominant 7th does the pushing.
Can I leave notes out of a dominant 7th chord?
Yes, the 5th is the usual candidate: G7 without the D still sounds like G7 because the root, 3rd and 7th carry the identity. Never leave out the 3rd or the 7th, because the tritone between them is the whole point of the chord.