A Augmented Triad

Chord Tones: A Augmented Triad

Symbol: aug, + — Formula: 1-3-♯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 augmented 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 augmented triad consists of two stacked major thirds, creating a symmetrical, ambiguous chord. Its raised fifth gives it a tense, unresolved quality that pulls toward resolution. The A Augmented Triad specifically contains 3 notes: A, C♯, F (formula: 1-3-♯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 Augmented Triad frequently appears in these progression patterns (shown in Roman numeral notation relative to key):

• Iaug-IV
• Vaug-I

Songs Featuring the Augmented Triad

Well-known songs where the A Augmented Triad — or this chord type — plays a prominent role:

• Oh! You Pretty Things – David Bowie
• All Blues – Miles Davis
• Michelle – The Beatles

Tuning Frequencies Across Temperaments

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

Scales Containing the A Augmented Triad

These scales include the A Augmented Triad as a diatonic or characteristic chord: