Where the seventh comes from
Remember the “skip one, take one” trick from the triads? Keep stacking one more third and you get to the seventh:
In C: C (D) E (F) G (A) B. This four-note chord is called four-note chord. The name “seventh” comes from B being the 7th note counting from C.
The seventh can be major (11 half steps, a half step below the octave) or minor (10 half steps, a whole step below the octave). Combining this with major, minor and diminished triads gives the five most common seventh chords.
The 5 most common seventh chords
| Chord symbol | Name | Formula | In C | How it sounds |
|---|---|---|---|---|
| C7 | Seventh (dominant) | 1 – 3 – 5 – ♭7 | C E G B♭ | Tense, wants to resolve |
| C7M | Major seventh | 1 – 3 – 5 – 7 | C E G B | Smooth, sophisticated (bossa, jazz) |
| Cm7 | Minor seventh | 1 – ♭3 – 5 – ♭7 | C E♭ G B♭ | Soft, melancholic |
| Cm7(♭5) | Half-diminished (Cø) | 1 – ♭3 – ♭5 – ♭7 | C E♭ G♭ B♭ | Unstable, preparation |
| C°7 | Diminished | 1 – ♭3 – ♭5 – 𝄫7 | C E♭ G♭ B𝄫 (sounds as A) | Very tense, passing |
C7: the dominant seventh chord
Triad major + seventh minor. When the chord symbol just says “7”, this is the seventh: minor. It's the most important chord in tonal music because it creates tension and wants to move to another chord (G7 → C, D7 → G, A7 → D…).
C7M: major seventh
Triad major + seventh major. In Brazil it's written 7M; in other countries it appears as maj7 or Δ. It sounds light, open, very common in bossa nova.
Cm7: minor seventh
Triad minor + seventh minor. Widely used in MPB, pop, soul and samba.
Cm7(♭5): half-diminished
Triad diminished + seventh minor. Also written Cø. It's the chord on the VII degree of the major scale (Bm7(♭5) in C) and shows up before the V in minor keys.
C°7: diminished seventh
Triad diminished + seventh diminished (9 half steps). It's three minor thirds in a row, so the chord splits the octave into equal parts and repeats every three frets on the guitar. In popular chord symbols, “C°” almost always already means this four-note chord.
Bonus: Cm(7M)
Triad minor + seventh major. Rare but beautiful: it's the classic suspense-scene sound and shows up in descending bass lines (Cm → Cm(7M) → Cm7 → Cm6).
Chord builder: pick and listen
Choose the root and the type. The keyboard shows the notes and degrees, and the button plays the chord.
Tap a button to listen. On your phone, turn off silent mode if there's no sound.
Learn by playing. In Dedilhado Vivo you see where each finger presses, play for real and the app checks you through the microphone. Free, no sign-up.
Open the free app →A practical rule for finding the seventh in any chord
- Find the root an octave higher.
- Go down a whole step (two keys, two frets): that's a minor seventh (for 7, m7 and m7(♭5)).
- Go down just half step: that's the major seventh (for 7M).
| Chord | Notes | Seventh |
|---|---|---|
| G7 | G B D F | minor |
| D7 | D F♯ A C | minor |
| A7 | A C♯ E G | minor |
| E7 | E G♯ B D | minor |
| B7 | B D♯ F♯ A | minor |
| F7M | F A C E | major |
| G7M | G B D F♯ | major |
| Am7 | A C E G | minor |
| Dm7 | D F A C | minor |
| Em7 | E G B D | minor |
| Bm7(♭5) | B D F A | minor |
Why G7 “pulls” toward C
G7 (G B D F) has a tritone between B and F. That interval is unstable. The B wants to rise a half step to C, and the F wants to drop a half step to E. Result: your ear “asks” for the C chord (C E G). That's why the dominant seventh chord shows up right before the return to the tonic in so many songs.
This is called cadence. See the II–V–I progression and much more in diatonic chords.
Seventh chords on guitar
Many seventh chords on guitar are just the plain chord with one finger added or lifted. Classic first-position examples:
| Chord | From the plain chord to the seventh chord |
|---|---|
| E → E7 | Lift your finger off the 4th string (D): it rings open and becomes the seventh (D). |
| A → A7 | Lift your finger off the 3rd string (G): it rings open and becomes the seventh (G). |
| Am → Am7 | Lift your finger off the 3rd string (G). |
| Em → Em7 | Play the open 4th string, or put finger 4 on the 3rd fret of the 2nd string (D). |
| D → D7 | Change the shape: C on the 1st fret of the 2nd string (the minor seventh of D). |
| C → C7M | Lift your finger off the 2nd string (C): it plays open B, the major seventh. |
In the app, the path for Chords and rhythm for guitar teaches E7, A7, D7 and others with the diagram and checks through the microphone that all the strings rang out.
How they appear in chord symbols
| You see | Means |
|---|---|
| 7 | minor seventh (dominant): C7 = C E G B♭ |
| 7M, maj7, Δ | major seventh: C7M = C E G B |
| m7, min7, -7 | minor with minor seventh |
| m7(♭5), m7b5, ø | half-diminished |
| °, dim, °7, dim7 | diminished (in practice, almost always with a diminished seventh) |
| m(7M), m(maj7) | minor with major seventh |
Now put the theory into your fingers
In Dedilhado Vivo you learn flute, guitar, violin or piano by seeing each finger on the screen, and the app listens to you play through the microphone.
Practice theory in the free appFrequently asked questions
What's the difference between C7 and C7M?
C7 has a minor seventh (B♭) and sounds tense, asking to resolve. C7M has a major seventh (B) and sounds smooth and stable. Only one note changes.
How is a seventh chord built?
Take the triad (1, 3, 5) and add the seventh note up from the root. If the chord symbol just says 7, it's a minor seventh (10 half steps); if it says 7M, it's a major seventh (11 half steps).
What does m7(b5) mean?
Minor chord with a diminished fifth and a minor seventh, also called half-diminished (ø). Example: Bm7(♭5) = B D F A.
Why is the seventh chord called dominant?
Because it shows up naturally on the V degree (the dominant) of the major scale. In C major, the V degree is G, and the chord built there is G7.
What's the difference between diminished and half-diminished?
Both have 1, ♭3 and ♭5. The half-diminished has a minor seventh (Cm7(♭5) with B♭); the diminished has a diminished seventh (C°7 with B𝄫, which sounds like A).