F#sus4 is F#, B and C# — F# with the third replaced by the fourth.
It sounds suspended mid-air. Played before the plain chord it is the oldest tension-and-release move there is.
Suspended — classically it resolves down onto the third.

| F# | B | C# |
|---|---|---|
| 1 | 4 | 5 |
Also written F#sus or F# suspended 4th. The same chord either way; which spelling you meet depends on who wrote the chart.
F#sus4 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.
5 of F#sus4’s 6 common shapes do this:244422xx4677x9967xx-9-11-11-12-914-x-11-11-12-14
All 6 common shapes as fret numbers, lowest string first. Hover or tap one to see it drawn.
Voice by voice, F#sus4 → F#. One voice moves by a semitone, and 2 notes are common to both chords.
| In F#sus4 | Moves | In F# |
|---|---|---|
| F#, the root | stays where it is | F#, the root |
| B, the fourth | falls a semitone | A#, the major third |
| C#, the fifth | stays where it is | C#, the fifth |
In which keys. Every note of F#sus4 belongs to C# minor (the iv), D major (the iii), Eb minor (the ♭III), E major (the ii), F# major (the I), F# minor (the i), Ab minor (the ♭VII), A major (the vi), B major (the V) and B minor (the v).
Every note of F#sus4 is in F# minor pentatonic, F# blues, F# major, F# mixolydian and F# dorian.
Change one note of F#sus4 and you have F# (the fourth becomes the major third), F#m (the fourth becomes the minor third), F#sus2 (the fourth becomes the second), F#sus2sus4 (add the second), F#5 (drop the fourth) or F#7sus4 (add the flat seventh).
F#sus4 is a suspended chord — root and fifth, with a second or fourth where the third would be — or nothing at all. Suspended and power chords on every root.
The common shapes and the derived voicings come from different places, and both are explained in how this site is built.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.