C#sus4

Q: What notes are in the C#sus4 chord?

The C#sus4 chord (C# Sus4) contains: C#, F#, G#. Its interval structure is shown above in the Theory section.

Q: How do I build C#sus4 on the keyboard?

Take the root and add the remaining chord tones following the interval formula. The highlight shows chord content, while the inversion control changes which chord tone is in the bass.

Q: Which keys is C#sus4 found in?

The chord acts as a diatonic degree in several keys — they are marked on the circle of fifths in the "Harmonic context" block.

Q: What can I substitute for C#sus4?

A substitution depends on harmonic function and voice leading, not only on shared tones. Computed options appear in the "Substitutions" block and should be checked in context.

C# Sus4

Octaves

Musical context

ChordC#sus4C# Sus4

ArpeggioC# majorBroken triad

ScaleC# major7 notes

KeyC# majorMajor key

ProgressionPop axisSequence

How the chord relates to the scale, mode, key and progression.

Theory

General info

Full name: C# Sus4
Symbol: C#sus4
Root: C#
Quality: Sus4

Chord notes

1C#root

4F#perfect 4th

5G#perfect 5th

Functions & resolutions

Typical function in key: ITonic (I)C# major
Stability / tension: Moderate tension — suspension awaits resolution
Most common resolutions: C#C# Major C#mC# Minor
Unstable degrees: 3F
4F#
resolves down to the 3rd
Main resolution: C#sus4source
C#C# Major
The suspended 4th in C#sus4 pulls down to the 3rd, resolving to C# major or minor.
Other resolutions: C#sus4source
Deceptive resolution
C#mC# Minor
C#sus4 can resolve to minor instead of major — the 4th drops to the minor 3rd.
C#sus4source
No resolution needed
In modal music, a sus chord may remain an independent sonority without 4–3 or 2–3 motion; with no 3rd, it defines neither major nor minor quality.
C#sus4source
Jazz reharmonization
C#7sus4C# 7sus4
In jazz, 7sus4 may retain its dominant bass and minor 7th without immediately resolving the 4th to the 3rd; it may also move to another sus chord.
C#sus4source
Functional resolution
F#F# Major
A sus chord can move up a 4th or down a step, functioning as a suspension from degrees other than the tonic.

Features

Character: No 3rd, with 4th-degree tension
Characteristic interval: Fourth instead of 3rd (4)
Description: The 4th replaces the 3rd, so the chord defines neither major nor minor quality. In a typical sus4 resolution, the 4th descends to the 3rd.
Application: Pop and rock (sus4 → major)
Pause before resolution
Building tension

Voicing & structure

Root position

v1C#(C#4)Bass

root

v2F#(F#4)P4from C#

v3G#(G#4)M2from F#

Harmony

Compatible scales

All chord tones are contained in these scales — use them for improvisation.

ScaleC# Minor pentatonic ScaleC# In (Japanese)ScaleC# Yo (Japanese)ScaleF# Major pentatonic ScaleF# Yo (Japanese)ScaleF# Akebono (Japanese)ScaleF# Hirajoshi (Japanese)ScaleG# Minor pentatonic ScaleG# Iwato (Japanese)ScaleD Chinese scale

This chord on guitar 🎸

See how C#sus4 looks on guitar.

Explore

Circle of fifths

Highlighted major keys contain this chord among their diatonic harmonies.

Relative key: BbmBb minor
Dominant: AbAb major
Subdominant: F#F# major
Key signature: 5 flats (Bb, Eb, Ab, Db, Gb)

What to learn next

ScaleC# Ionian (major)Scale to improvise over this chord ChordC# MajorA nearby chord on the same root — compare the sound PracticeChord trainerLock the fingering into muscle memory ProgressionChord progressionsHow this chord works inside real progressions ChordC# Sus2Another related chord to practise

Recommended for you

C# MajorA chord that sounds close

C# Sus2A chord that sounds close

C# 7sus4A chord that sounds close

C# Ionian (major)A scale related to this chord

C# DorianA scale related to this chord

Practice

Keyboard Trainer

Reinforce it in practice — play and name notes on the interactive keyboard.

Open Trainer

Test yourself

(Press any key to start)

What notes are in the C#sus4 chord?

How do I build C#sus4 on the keyboard?

Which keys is C#sus4 found in?

What can I substitute for C#sus4?