Dominant Seventh Chord

 

The simplest way to think of a seventh chord is three thirds stacked on top of each other.

The dominant seventh is the most important of the seventh chords and is fundamental to Western harmony. A useful shortcut is to think of a dominant seventh chord as a major triad with a minor third on top.

If we play a G major triad, for example:

… we can add the note a minor third above the top note:

This forms a G dominant seventh chord. It’s often called G7 for short.

More precisely, a dominant seventh is a chord that consists of a major third, perfect fifth, and minor seventh above a root.

Let’s try another example. If we take C as our root, a major third above C is E:

A perfect fifth above C is G:

If we combine a major third and perfect fifth above the same root, we get a major triad:

Finally, a minor seventh above C is B-flat:

If we add our minor seventh to the other notes, we get a C dominant seventh chord:

Major-minor seventh

The dominant seventh chord is sometimes also called a major-minor seventh. “Major” refers to the major third, while “minor” refers to the minor seventh. (The perfect fifth is assumed.)

Terminology

What’s the difference between a “C dominant seventh” and the “dominant seventh of C”? The terminology can be rather confusing, so let me clarify some frequent terms you’re likely to encounter.

C dominant seventh, C major-minor seventh and C7 all refer to the same chord:

This chord is built on the note C, which means that C is the root of the chord. (Even if C is not the lowest note—in other words, if the chord is inverted, as long as we have exactly this combination of notes, C, E, G and B-flat, C is still the root of the chord.)

Importantly, the C7 chord is independent of key: You could play in any key, with any key signature, and if you encounter the notes C, E, G and B-flat played as a chord, you’ll play a C7 chord.

Dominant seventh of C refers to a different chord, however. This refers to the dominant seventh chord in the key of C, or the dominant seventh chord that resolves to C. “C” can be C major or C minor: It doesn’t actually matter because the dominant seventh of C major is the same as the dominant seventh of C minor.

“Dominant” refers to the fifth scale degree, in other words, the fifth note of the scale. Let’s continue using the scale of C major. The notes of the C major scale are C, D, E, F, G, A, B. The fifth note of the scale is G.

If we build a chord on scale degree 5—in this case G—using only the notes within the scale, we play a dominant chord, also called dominant triad:

This chord is still a triad because there are only three notes.

If we then add the seventh from scale degree 5—in other words, the note in the C major scale that is a seventh away from G—we now get the dominant seventh of C:

To clarify, here are some terms you might encounter:

C dominant seventh is the dominant seventh chord built on C. It consists of the notes C, E, G and B-flat:

The dominant seventh of C refers to the dominant seventh chord that resolves to C (either C major or C minor). It is built on the dominant of C, in other words, the fifth note of the C major (or C minor) scale, G. It consists of the notes G, B, D and F:

Summary

As a summary, just remember two things:

  1. There is a simple shortcut for building a dominant seventh chord on any note: Play a major triad, then add a minor third on top. These are the notes of the dominant seventh chord.
  2. The dominant is the fifth note of any scale. If we build a major triad on this note, we’ll get the dominant chord, also called the dominant triad. If we use only the notes of the scale and add the seventh—meaning the note a seventh above the dominant—we’ll get a dominant seventh chord. An easy shortcut is to start on the fifth note of a scale, then play a total of four notes, skipping over every other note.

With these shortcuts you can now build a dominant seventh chord on any note and find the dominant seventh chord in any scale.

Stay connected with news and updates!

Join our mailing list to receive the latest news and updates from our team.
Don't worry, your information will not be shared.

Join Now