F#aug is F#, A# and D — F# with the fifth raised a semitone.
It sounds stretched, and suspended between keys. Its commonest job is passing between a major triad and its sixth or seventh, with the raised fifth as a single voice walking up.

| F# | A# | D |
|---|---|---|
| 1 | 3 | ♯5 |
Passing chord — it belongs to no key in particular.
Also written F#+, F#(#5) or F# augmented. The same chord either way; which spelling you meet depends on who wrote the chart.
F#aug in root position puts F# in the bass, which is the chord as it is spelled: the note it is named after underneath everything else.
7 of F#aug’s 8 common shapes do this: 2x4332, xx4332, x9877x, x-9-x-11-11-10, x-9-12-11-11-x, x-x-x-11-11-10, 14-13-12-11-11-x.
Start with xx4332 — down at the nut. None of the shapes for F#aug uses an open string, so every one of them is movable; the lowest sits at the 2nd fret. None of them needs a barre. Together they cover the neck from the 2nd fret to the 14th.
| Frets | Where | Bass | Top | Hand |
|---|---|---|---|---|
| 2x4332 | 2nd fret | F#, root position | F# | all fretted |
| xx4332 | 2nd fret | F#, root position | F# | all fretted |
| xx8776 | 6th fret | A#, 1st inversion | A# | all fretted |
| x9877x | 7th fret | F#, root position | F# | all fretted |
| x-9-x-11-11-10 | 9th fret | F#, root position | D | all fretted |
| x-9-12-11-11-x | 9th fret | F#, root position | A# | all fretted |
| x-x-x-11-11-10 | 10th fret | F#, root position | D | all fretted |
| 14-13-12-11-11-x | 11th fret | F#, root position | A# | all fretted |
The same notes rebuilt from scratch give 45 triad voicings, each on its own page.
Every note of F#aug is in F# whole tone and F# altered.
Change one note of F#aug and you have F# (the sharp fifth becomes a fifth), F#maj7#5 (add the major seventh) or F#aug7 (add the flat seventh).
F#aug is a augmented chord — root, major third, sharp fifth. Augmented chords on every root.
On F#aug’s sound and use this page follows Stefan Kostka, Dorothy Payne & Byron Almén, Tonal Harmony (McGraw-Hill, 8th ed., 2018). The shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.