F♯ Suspended 4th Chord

Chord Tones: F♯ Suspended 4th Chord

Symbol: sus4, sus — Formula: 1-4-5

DegreeNoteFrequency (A=440, Equal)
1 F♯4 369.994 Hz
4 B4 493.883 Hz
5 C♯4 277.183 Hz

Chord Notation

Notation TypeSymbol / Value
Lead Sheet SymbolF♯sus4
All Common Symbolssus4, sus
Interval Formula1-4-5
Harmonic Categoryopen

Roman numeral (e.g. I, IV, V) and Nashville Number notation are key-dependent. See Keys pages for chord function within specific keys.

Inversions

InversionNotes (low to high)Bass NoteSlash Notation
Root Position F♯4 B4 C♯4 F♯ F♯ Suspended 4th Chord
First Inversion B4 C♯4 F♯4 B F♯ Suspended 4th Chord/B
Second Inversion C♯4 F♯4 B4 C♯ F♯ Suspended 4th Chord/C♯

Harmonic Function

The F♯ sus4 chord commonly functions as the tritone substitution in C major or tonic in F♯ major. Its harmonic role varies by key — in major keys it provides stable harmonic grounding.

The sus4 chord replaces the third with a perfect fourth, creating tension that traditionally resolves down to the major third. It creates anticipation and is common before dominant chords. The F♯ Suspended 4th Chord specifically contains 3 notes: F♯, B, C♯ (formula: 1-4-5). On piano, F#-rooted chords place the root on a black key, creating hand positions that many pianists find ergonomically comfortable for fast passages. Progressive rock, jazz fusion, and electronic music use F#-rooted chords to create unexpected harmonic shifts and chromatic modulations.

Common Progressions

The F♯ Suspended 4th Chord frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

Songs Featuring the Suspended 4th Chord

Well-known songs where the F♯ Suspended 4th Chord — or this chord type — plays a prominent role:

Tuning Frequencies Across Temperaments

Frequencies shown at A=440 Hz. View full temperament data for any note.

NoteEqual Temp.PythagoreanJust Intonation
F♯4 369.994 Hz 371.251 Hz 367.911 Hz
B4 493.883 Hz 495.000 Hz 490.548 Hz
C♯4 277.183 Hz 278.437 Hz 279.067 Hz

Scales Containing the F♯ Suspended 4th Chord

These scales include the F♯ Suspended 4th Chord as a diatonic or characteristic chord: