The Augmented Triad · Jazz Wiki

Stack two major thirds on top of each other and you get a chord that refuses to sit still: the augmented triad. Unlike a plain major or minor triad, it has no perfect fifth to act as a stable anchor — every note is the same distance from its neighbor, so the chord has nowhere natural to rest. That built-in restlessness is exactly why jazz players reach for it: it wants to move, and you get to decide where.

What It’s Built From

An augmented triad is root, major third, and augmented fifth — two identical four-semitone leaps stacked on each other.

C aug = C – E – G♯ (root, M3, M3)
F aug = F – A – C♯
B♭ aug = B♭ – D – F♯
E♭ aug = E♭ – G – B

Here are those four triads on the staff, root position:

Notice there’s no perfect fifth anywhere in that spelling. That missing fifth is the whole story: it’s what makes the chord sound suspended in air rather than planted on the ground, in contrast to the grounded feel a fifth gives ordinary triads (see Intervals for why the fifth matters so much to our ear’s sense of stability).

Why It’s Perfectly Symmetrical

Because both intervals inside the chord are identical major thirds, the augmented triad divides the octave into three exactly equal parts (four semitones each, 4+4+4=12). That symmetry has a striking consequence: there are only four distinct augmented triads in all of music, because stacking a third one just brings you back to the first note an octave up.

C aug = E aug = G♯ aug (all the same three pitches, just renamed by enharmonic spelling)
Its inversions aren’t really new chords — they’re the same notes reheard with a different root on the bottom

C augmented is an equilateral triangle on the chromatic clock — three identical major thirds (4+4+4 semitones) close the octave, so only four distinct augmented triads exist in all of music

This is the same logic that makes the Whole Tone Scale special: an augmented triad is simply every other note of a whole-tone scale, and a whole-tone scale is two overlapping augmented triads a whole step apart. Because the chord has no unique “home” note, it’s harmonically rootless — useful for sliding between distant keys without any single pitch pulling rank.

The V+ Move: Turning Instability Into Motion

The most common home for the augmented triad in jazz is as an altered dominant — V+ (also written V7♯5), where the raised fifth becomes a chromatic lever pulling into the tonic.

G+ (G – B – D♯) → Cmaj7: the D♯ resolves up by half step to E, the third of C
This is really G7♯5 with the seventh dropped — see The Augmented Dominant for the full four-note version and Chord Alterations for how ♯5 fits alongside other altered tensions like ♭9 and ♯9

Here’s that G+ resolving into Cmaj7, with D♯ climbing to E on top:

That single half-step pull (D♯ to E) is the augmented triad doing its real job: converting pure symmetry into directed Tension and Release. It’s the same chromatic-voice-leading trick used in a Line Cliche, where an inner voice creeps up or down by half steps while the chord above it holds steady.

Where the Chord Shows Up Naturally

Augmented triads aren’t diatonic to major or natural minor, but they do occur on scale degree ♭III (or III) inside two scales you already use constantly.

♭III+ in The Harmonic Minor Scale: in C harmonic minor, E♭ aug = E♭ – G – B
III+ in The Melodic Minor Scale: in F melodic minor, A♭ aug = A♭ – C – E

John Coltrane pushed the symmetry idea to its extreme, building whole tune structures — most famously the key centers of “Giant Steps” — around root motion that traces an augmented triad a major third at a time; that story is worth its own detour in Coltrane Changes.

Those three key centers, laid out as ascending roots, trace the augmented triad directly:

♫ Listen

Gerry Mulligan Quartet with Chet Baker — “My Funny Valentine” (Pacific Jazz, 1952): the opening line cliché holds a C minor chord while an inner voice slips down chromatically; the second chord, Cm(maj7), contains E♭–G–B — an augmented triad hiding inside a minor chord, and you can hear its ache.
John Coltrane — “Giant Steps” (Giant Steps, 1960): the three key centers of the whole composition — B, E♭, G — are themselves the three notes of an augmented triad; you can hear the tenor chase that cycle from the very start of the head.
Wayne Shorter — “Juju” (Juju, 1964): the tune opens on a sustained B augmented chord with McCoy Tyner coloring it in whole-tone voicings — a clear, exposed example of the chord’s suspended, rootless character.