Major, Minor, and Dominant Seventh Chords

In this lesson, we will explore major, minor, and dominant seventh chords. Previously, you learned how to form and invert major, minor, and diminished triads. Now, we’ll expand this knowledge to chords built with four notes, known as seventh chords.

Chord Types by Number of Keys

Dominant Seventh Chords

The V chord in a key is called the dominant seventh chord (or simply "dominant chord"). For example, in C Major, the dominant is G.

• G Major Triad: G, B, D.
• To build a dominant seventh chord, add a minor third above the triad:
  G7: G, B, D, F.

Formula for Dominant Seventh Chords

Major Triad (root + major third + perfect fifth) + Minor Third = Dominant 7th Chord  

Example in C Major:

1. Start with the G Major triad (G, B, D).
2. Add the minor third (F) above the triad → G7 (G, B, D, F).

default:
  Piano.Chart: C7, Db7, D7, Eb7, E7, F7, Gb7, G7, Ab7, A, Bb7, B7

Quick Tip:

• Find the dominant (V) note of the key.
• Add the 4th scale degree (a minor third above the triad).

Major Seventh Chords

A major seventh chord is built by adding a major third to a major triad.

Formula:

Major Triad + Major Third = Major 7th Chord  

Example in C Major:

• C Major Triad: C, E, G.
• Add a major third (B) → Cmaj7 (C, E, G, B).

default:
  Piano.Chart: M7

Note:

• In C Major and F Major, these chords use only white keys. In other keys, they may include black keys.
• A major seventh chord never consists entirely of black keys.

Minor Seventh Chords

A minor seventh chord is built by adding a minor third to a minor triad.

Formula:

Minor Triad (root + minor third + perfect fifth) + Minor Third = Minor 7th Chord  

Example in C Minor:

• C Minor Triad: C, Eb, G.
• Add a minor third (Bb) → Cm7 (C, Eb, G, Bb).

default:
  Piano.Chart: m7

Alternative Approach:

• Lower the third of a dominant seventh chord (e.g., C7 → C, E, G, Bb becomes Cm7 → C, Eb, G, Bb).

Inversions of Seventh Chords

The inversion rules for triads also apply to seventh chords:

1. Root Position: Root is the lowest note.
2. First Inversion: Third is the lowest note.
3. Second Inversion: Fifth is the lowest note.
4. Third Inversion: Seventh is the lowest note.

Example (C7):

• Root Position: C, E, G, Bb
• First Inversion: E, G, Bb, C
• Second Inversion: G, Bb, C, E
• Third Inversion: Bb, C, E, G

Reference Charts

Dominant Seventh Chords

Major Seventh Chords

Minor Seventh Chords

Key Takeaways

• Dominant 7th: Major triad + minor third (creates tension).
• Major 7th: Major triad + major third (smooth, jazzy sound).
• Minor 7th: Minor triad + minor third (moody, soulful sound).