Concise theory and examples
Chord reference
The formulas show the sequence of intervals used to build each chord. The tables include chord symbols and keyboard examples built on C.
Two or three notes
Triads, suspended and power chords
| Type | Trainer symbol | Other symbols | Formula | Example from C |
|---|---|---|---|---|
| Major triad | C | Cmaj | M3 + m3 | C–E–G |
| Minor triad | Cm | Cmin, C− | m3 + M3 | C–E♭–G |
| Diminished triad | Cdim | C° | m3 + m3 | C–E♭–G♭ |
| Augmented triad | Caug | C+ | M3 + M3 | C–E–G♯ |
| Suspended second | Csus2 | — | M2 + P4 | C–D–G |
| Suspended fourth | Csus4 | Csus | P4 + M2 | C–F–G |
| Power chord | C5 | — | P5 | C–G · two notes only |
Four notes
Seventh and sixth chords
| Type | Trainer symbol | Other symbols | Formula | Example from C |
|---|---|---|---|---|
| Dominant seventh | C7 | — | M3 + m3 + m3 | C–E–G–B♭ |
| Major seventh | Cmaj7 | CΔ7, CM7 | M3 + m3 + M3 | C–E–G–B |
| Minor seventh | Cm7 | Cmin7, C−7 | m3 + M3 + m3 | C–E♭–G–B♭ |
| Half-diminished seventh | Cm7♭5 | Cø7 | m3 + m3 + M3 | C–E♭–G♭–B♭ |
| Diminished seventh | Cdim7 | C°7 | m3 + m3 + m3 | C–E♭–G♭–B♭♭ |
| Major sixth | C6 | Cmaj6 | M3 + m3 + M2 | C–E–G–A |
| Minor sixth | Cm6 | Cmin6 | m3 + M3 + M2 | C–E♭–G–A |
Why B♭♭ rather than A? Cdim7 is written as a chain of thirds: C–E♭–G♭–B♭♭. B♭♭ sounds like A on the keyboard; the trainer notes this enharmonic equivalent in brackets on the staff.
Advanced section
Less common seventh chords
| Type | Symbol | Formula | Example from C |
|---|---|---|---|
| Minor-major seventh | Cm(maj7) | m3 + M3 + M3 | C–E♭–G–B |
| Augmented major seventh | Cmaj7♯5 | M3 + M3 + m3 | C–E–G♯–B |
| Augmented dominant seventh | C7♯5 | M3 + M3 + d3 | C–E–G♯–B♭ |
| Diminished major seventh | Cdim(maj7) | m3 + m3 + A3 | C–E♭–G♭–B |
Inversions
What the slash means
C/E means a C major chord with E as its lowest note: E–G–C. Dm/F is D minor with F in the bass: F–A–D. The trainer uses inversions only, so the note after the slash always belongs to the chord; non-chord bass symbols such as C/D are not included.
| Symbol | Voicing | Keyboard |
|---|---|---|
C/E | E–G–C | The dark key is bass E |
C/G | G–C–E | The dark key is bass G |
Cmaj7/E | E–G–B–C | The dark key is bass E |
Cmaj7/G | G–B–C–E | The dark key is bass G |
Cmaj7/B | B–C–E–G | The dark key is bass B |
In inversion exercises, the root does not have to be the lowest note: play the bass specified after the slash.
Open Chord Trainer
Next step
From chord practice to confident playing
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