Major 7, minor 7, dominant 7.

Now that you know triads (root, 3rd, and 5th), you can probably guess where this is going.

Seventh chords are what you get when you stack another third on top of a triad. Root, 3rd, 5th, and 7th.

This also implies that you could keep stacking thirds to get even more extended chords. Stack another third and you get a 9th chord, then 11ths, even 13ths. We'll come back to those later. For now, let's focus on the three seventh chords you'll see the most.

Start with a major triad and add a major seventh on top. That's the note 11 half steps above the root, or one half step below the octave.

  • Root to 3rd: major third (4 half steps)
  • 3rd to 5th: minor third (3 half steps)
  • 5th to 7th: major third (4 half steps)
  • Root to 7th: major seventh (11 half steps)

Cmaj7: C — E — G — B

Major seventh chords sound smooth, warm, a little dreamy. You'll hear them all over jazz, R&B, neo-soul, and anytime a songwriter wants something that feels lush without being tense. Think of the opening chord of "Don't Know Why" by Norah Jones, or basically any lo-fi hip hop beat.

In chord charts you'll see these written as Cmaj7, Fmaj7, Dmaj7, etc. Sometimes you'll also see a triangle: CΔ7 or just CΔ. Same thing.

Start with a minor triad and add a minor seventh. That's 10 half steps above the root, or two half steps below the octave.

  • Root to 3rd: minor third (3 half steps)
  • 3rd to 5th: major third (4 half steps)
  • 5th to 7th: minor third (3 half steps)
  • Root to 7th: minor seventh (10 half steps)

Am7: A — C — E — G

Minor seventh chords sound mellow and relaxed. They're everywhere: pop, R&B, funk, jazz. A plain minor chord sounds a little stark sometimes; adding the 7th softens it up. If you've ever played a chord labeled Am7, Dm7, or Em7 on a chart, this is what that is.

Written as Am7, Dm7, Em7, etc. Sometimes Amin7 or A-7.

This is the big one. Start with a major triad and add a minor seventh. Not major. Minor. That combination of a major third on the bottom and a minor seventh on top creates a sound that wants to move. It sounds like it's pulling toward something.

  • Root to 3rd: major third (4 half steps)
  • 3rd to 5th: minor third (3 half steps)
  • 5th to 7th: minor third (3 half steps)
  • Root to 7th: minor seventh (10 half steps)

G7: G — B — D — F

Dominant seventh chords are the engine of tension and resolution in most Western music. We'll dig into why in the next unit when we talk about how chords function together. For now, just know that when you see a chord labeled G7 or C7 or E7 (no "maj," no "m," just a 7) that's a dominant seventh. It's the most common type of seventh chord in blues, rock, and pop.

The reason it's called "dominant" will make a lot more sense when we get to harmonic function. Short version: the dominant seventh chord naturally appears on the 5th degree (the "dominant") of a major key, and it's the chord that most strongly pulls you back home to the I chord.

Seventh chord Triad 7th type Symbol
Major seventh Major triad Major 7th (11) maj7, Δ7
Minor seventh Minor triad Minor 7th (10) m7, min7, -7
Dominant seventh Major triad Minor 7th (10) 7

Notice that the dominant seventh is the odd one out. It's the only one where the triad quality and the seventh quality don't match. Major triad, minor seventh. That mismatch is where the tension comes from.

There are more seventh chord types, but these three cover the vast majority of what you'll encounter in pop, rock, folk, blues, and R&B. Two others worth knowing exist:

Minor-major seventh (mMaj7): minor triad with a major seventh. Sounds dark and tense. You'll hear it in film scores and jazz. Not common in pop.

Diminished seventh (dim7 or °7): diminished triad with a diminished seventh (9 half steps). Every note is a minor third apart. Sounds very dramatic. Classic "villain music" chord.

Half-diminished seventh (m7b5 or ø7): diminished triad with a minor seventh. Shows up naturally on the 7th degree of a major key, the same spot where the diminished triad lives. Common in jazz, less so in pop.

Don't worry about memorizing these right now. If you know major 7, minor 7, and dominant 7, you've got the ones that matter most.

Here's a trick. When you flip a 7th upside down (move the bottom note up an octave, or the top note down), you get a 2nd. And you've been comfortable with 2nds since the very first unit of this course, because 2nds are just half steps and whole steps.

A major 7th inverts to a minor 2nd (a half step). Look at C to B: that's 11 half steps, a major 7th. Now flip it. B to C is just 1 half step, a minor 2nd.

A minor 7th inverts to a major 2nd (a whole step). D to C: 10 half steps, a minor 7th. Flip it. C to D is 2 half steps, a whole step.

So if you're staring at a 7th on the staff and can't tell whether it's major or minor, just look at the gap between the top note and the next octave of the bottom note. If that gap is a half step, it's a major 7th. If it's a whole step, it's a minor 7th.

The resources here are especially valuable to really be able to hear how adding a 7th transforms the sound of chords, even if the concept itself is fairly straightforward.

On your instrument, take chords you already know and add the seventh. If you can play a G major, find the F and add it. Now you've got G7. Turn that Am into Am7 by adding the G. Play through a few chord progressions you know and try swapping in seventh chords to hear how they change the feel. They won't always sound right, but when they do, you'll know it immediately.

You probably understand what seventh chords are at this point. The harder part is getting fluent enough that you can see or hear a seventh and immediately know its quality without counting half steps. That takes time and repetition. Start here:

Now try identifying full seventh chords. You'll see a four-note chord on the staff and need to tell whether it's a major 7th, minor 7th, or dominant 7th:

For more practice, the Interval Trainer lets you select specific intervals to drill. Set it to 3rds and 7ths only and you'll be training the two intervals that matter most for building and identifying chords. The Note Trainer also has a chord mode where you can drill all the seventh chord types together.