What Is an Augmented Triad?
An augmented triad is a three-note chord that sounds eerie, ambiguous, and unresolved. It's built from a root note, a major third, and an augmented fifth — a raised perfect fifth.
Augmented triads are unique because of their perfect symmetry: each interval is exactly 4 semitones. This creates a "floating" quality — the chord seems to lack a gravitational center. You don't know which note is the root. It's disorienting, mysterious, and musically unusual.
How to Build an Augmented Triad
Formula
Root + 4 semitones + 4 semitones
Or: Root + Major 3rd + Augmented 5th
To build any augmented triad, pick a root note and count up from there.
Example: C Augmented Triad
- C (root)
- E (4 semitones up from C = major third)
- G# (4 semitones up from E = augmented fifth, or 8 semitones up from C)
The augmented fifth — exactly 8 semitones — is what creates the eerie quality. A perfect fifth (7 semitones) feels natural and stable. Sharpen it by a semitone and suddenly the chord feels wrong, unnatural, floating.
All 12 Augmented Triads
| Chord | Root | Major 3rd | Augmented 5th |
|---|---|---|---|
| C+ | C | E | G# |
| G+ | G | B | D# |
| D+ | D | F# | A# |
| A+ | A | C# | E# |
| E+ | E | G# | B# |
| B+ | B | D# | Fx |
| F#+ | F# | A# | Cx |
| F+ | F | A | C# |
| B♭+ | B♭ | D | F# |
| E♭+ | E♭ | G | B |
| A♭+ | A♭ | C | E |
| D♭+ | D♭ | F | A |
The Sound of an Augmented Triad
Eerie, unresolved, ambiguous, floating, mysterious, supernatural.
Augmented triads sound wrong on purpose. They're not as commonly used as major, minor, or diminished triads. But in the right context — film scores, progressive music, experimental composition — they create a unique atmospheric effect. They sound like you're suspended in space, neither major nor minor, neither resolved nor fully tense.
The Symmetry Problem
Here's what makes augmented triads fascinating and unusual: because each interval is exactly equal (4 semitones), an augmented triad can be spelled three different ways and still sound identical.
All three are enharmonically identical:
C E G# = E G# C = G# C E
This symmetry means augmented triads have no real harmonic "root" — all three notes are equally valid.
How to Use Augmented Triads
1. For dramatic effect: Use augmented triads in film scores, ambient music, or experimental composition to create mystery or otherworldliness.
2. As passing chords: Use them briefly between more stable chords for chromatic movement and texture.
3. In extended harmony: Augmented triads work well in jazz and contemporary classical music as colour chords.
4. For emotion: Create unsettling or transcendent moments in your music.
Free: Chord Ear Training Cheat Sheet
Learn to recognize the unique floating quality of augmented triads.