Aaug Chord on Guitar
Aaug = A – C# – F (Root, Major 3rd, Minor 6th)
A augmented stacks two major thirds on top of the root, giving it — like the diminished seventh chord but built from a different interval — a fully symmetrical structure. At the fifth-fret barre, that symmetry means Aaug shares its exact three notes with only two other augmented triads on the entire fretboard.
The notes are A, C#, F (enharmonically E#), a triad of root, major third, and sharp fifth. Because a major third stacked on a major third stacked on a major third eventually returns to the starting pitch class after three steps, A augmented, C# augmented, and F augmented are all built from the identical three notes — only the note treated as the root differs. Musically the raised fifth gives the chord a restless, unresolved brightness quite different from the murkier tension of a diminished chord; augmented triads are used as a way to push a major chord's fifth upward, often as a brief chromatic move into the following chord's root or third.
Fingerings
Barre (5th fret)
How to Practice It
Because Aaug, C#aug, and Faug are physically the same three notes, try naming the chord all three ways as you play it, then resolve it to a major chord built on each of those three roots to hear how differently the identical shape can be used depending on where it's headed. The raised fifth is the note to focus on by ear — it's the one pitch that distinguishes this chord from a plain A major triad.
Common Progressions
- A – Aaug – D (I – I+ – IV, using the raised fifth as a chromatic lead-in)
- F – Aaug – A (illustrating the shared-note relationship resolving to A)
- C#m – Aaug – F#m (using the augmented triad as a connective chromatic chord)
- A – Aaug – A6 – A7 (a classic ascending-chromatic-line cliché)
FAQ
- What notes make up A augmented?
- A, C#, and F (or E#, enharmonically) — root, major third, and sharp fifth, with the raised fifth being the note that sets it apart from a plain A major triad.
- Why can Aaug also be called C#aug or Faug?
- An augmented triad is built from two stacked major thirds, and because three major thirds evenly divide the octave, the same three notes can be spelled starting from any of the three pitches involved, producing three equally valid names for one chord shape.
- How is Aaug different from Adim7 in terms of symmetry?
- Both are symmetrical, but Adim7's minor-third stacking gives it four equally valid roots, while Aaug's major-third stacking gives it only three — the two chords divide the octave differently, which is why one repeats every three frets and the other every four.
- What's the typical use for an augmented triad in a progression?
- It's most often used as a brief chromatic passing chord, raising a major triad's fifth by a half step to create forward motion into the next chord, rather than as a chord a progression settles on for any length of time.
- Is Aaug hard to finger compared to plain A major?
- It's a similarly compact barre shape, generally no harder than the plain triad, though the raised fifth changes which finger lands where compared to the familiar A-major shape.
- Does Aaug appear naturally in the A major scale?
- No — augmented triads aren't diatonic to the major scale in standard practice; Aaug is a chromatically altered chord, most often reached by raising the fifth of a plain A major triad for a specific melodic or harmonic effect rather than occurring as part of A major's built-in harmony.
- How does the ear typically perceive an augmented triad?
- As bright but unsettled — the raised fifth keeps the chord from resolving the way a plain major triad does, giving it a slightly eerie, suspended quality that composers use deliberately when they want a moment of harmonic ambiguity.
Aaug on other instruments: Aaug on Piano. Related: how chords are built, chord finder.