A Suspended 4th Chord

Chord Tones: A Suspended 4th Chord

Symbol: sus4, sus — Formula: 1-4-5

Chord Notation

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

Inversions

Harmonic Function

The A sus4 chord commonly functions as the submediant (vi) in C major or dominant (V) in D 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 A Suspended 4th Chord specifically contains 3 notes: A, D, E (formula: 1-4-5). On guitar, A-rooted chords anchor to the open A string (5th string), and barre chord shapes rooted on A form the basis of the "A-shape" CAGED system. Blues, rock, and country music use A-rooted chords extensively — the classic 12-bar blues often starts on A, and many rock power chord riffs center on the open A string.

Common Progressions

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

• Vsus4-V-I
• Isus4-I

Songs Featuring the Suspended 4th Chord

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

• Scarborough Fair – Simon & Garfunkel
• The Seeker – The Who
• Born on the Bayou – CCR

Tuning Frequencies Across Temperaments

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

Scales Containing the A Suspended 4th Chord

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