Lesson 10 · All 12 keys

Augmented Chord Triad Trainer

Learn how an augmented triad is built one semitone-count at a time, then put it to work with two MIDI exercises: playing all 12 augmented chords around the circle of fourths, and a pleasant four-chord progression — containing just one augmented chord — in every key.

How an augmented triad is built

A triad is a 3-note chord. Every augmented triad — in any of the 12 keys — is built the exact same way, by counting semitones to the right from a root note:

  1. Start on the root — the note that names the chord.
  2. Count 4 semitones to the right to land on the major 3rd.
  3. From there, count 4 more semitones to the right (8 semitones from the root) to land on the augmented 5th.
Example — C augmented: start on C, count 4 semitones right to reach E, then count 4 more semitones right to reach G♯. C‑E‑G♯ is the C augmented triad. The pattern 4 then 4 (8 semitones total from root to top) is what makes a triad "augmented" — every one of the 12 augmented chords is this same shape, just moved to start on a different key.
Compare this to a major triad, which counts 4 then 3 semitones instead — the augmented triad simply raises that perfect 5th by one more semitone, turning it into an augmented 5th. Because an augmented triad is built entirely from two identical major-3rd stacks (4 + 4 + 4 = 12, exactly one octave), it is perfectly symmetrical: every one of its three notes could equally well be called the "root", and the chord sounds identical no matter which note you start counting from. That symmetry is also what gives it its restless, unresolved sound — it doesn't belong to any one key, which is exactly why it works so well as a passing chord between two others.

Try it: pick a root and build the chord step by step

Step 1 of 3
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Chord toneNoteSemitones from rootMIDI #

All 12 augmented triads at a glance

ChordRoot+4 semitones → 3rd+4 semitones → aug 5th

This MIDI exercise plays all 12 augmented chords, one after another, moving around the circle of fourths — each chord's root sits a perfect 4th (5 semitones) above the last one: C → F → B♭ → E♭ → A♭ → D♭ → G♭/F♯ → B → E → A → D → G → back to C. Every chord is played as a full triad (root, 3rd, and augmented 5th together).

Chord 1 of 12
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The 12 chords, in circle-of-fourths order

#ChordRoot3rdAug 5th

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Key of C
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Progression in C

DegreeChordRoot3rd5th