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The A chord

Three fingers on adjacent strings, second fret. Easier to play than to make sound interesting. The A (A - C# - E) is a major triad, which is why it sounds the open arrival point of a phrase. Writers pick it for a singalong opening, and you can find it across pop, folk, country and rock. On guitar the chord sits in barre-chord territory for most useful keys; on piano it stacks straight up under the right hand. The page below covers the voicings worth memorising, the theory, the progressions where the A earns its keep, and the records that lean on it.

Hear the A in the chord builder →
Scale degrees Note names

Voicings for A

Common ways to grip the A on guitar and piano. Guitar diagrams read low E to high E left-to-right; an × means muted, an open circle above the nut means an open string. Filled dots are fretted notes.

Guitar , full chord shapes

CAGED-derived voicings for A across the neck. Pick the shape closest to where your hand already sits.

Guitar: E shape at fr.5
Notes: A - C# - E (chord tones)
Guitar: A shape at fr.2
Notes: A - C# - E (chord tones)
Guitar: D shape at fr.7
Notes: A - C# - E (chord tones)
Guitar: C shape at fr.9
Notes: A - C# - E (chord tones)
Guitar: G shape at fr.2
Notes: A - C# - E (chord tones)
Guitar: top-4 voicing
Notes: A - C# - E (chord tones)

Guitar , triad shapes

Three-note triad shapes on each string set, shown moving up the neck. Light textures for arpeggios, pop layering and chord-melody work.

Triad: top strings (G-B-e) · open
Notes: top-string triad, open
Triad: top strings (G-B-e) · fr.5
Notes: top-string triad, fr.5
Triad: top strings (G-B-e) · fr.9
Notes: top-string triad, fr.9
Triad: middle strings (D-G-B) · fr.2
Notes: middle-string triad, fr.2
Triad: middle strings (D-G-B) · fr.5
Notes: middle-string triad, fr.5
Triad: middle strings (D-G-B) · fr.9
Notes: middle-string triad, fr.9
Triad: bass strings (A-D-G) · fr.2
Notes: bass-side triad, fr.2
Triad: bass strings (A-D-G) · fr.6
Notes: bass-side triad, fr.6
Triad: bass strings (A-D-G) · fr.9
Notes: bass-side triad, fr.9

Piano voicings

Root position and inversions. The bass note matters: each inversion changes how the chord sits under a melody.

Piano: root position
Notes: A - C# - E. Root A at the bottom. The classic stacked-thirds spelling of a major triad.
Piano: first inversion
Notes: C# - E - A. C# at the bottom. Common in chord-melody, walking bass lines and gentler voicings.
Piano: second inversion
Notes: E - A - C#. E at the bottom. A floating, suspended feel often used in hymns and ballads.

The theory behind A

A is a major triad built on A. Its three or four notes (A - C# - E) sit a specific distance apart: root, major third, perfect fifth. That makes it a Dominant (V) in the key of D major, and the same chord works as the Tonic (I) in A major. The simplest rule of thumb: the A wants to stay home or move to the IV or V.

Progressions that use A

Short progressions that put the A to work. Each one is shown in a different key so you can pick the one that suits your singer.

IVviIV key of D major
D - A - Bm - G

The four-chord engine behind a thousand pop hits. The lift from I to V opens the chorus, vi pulls down into feeling, IV walks back toward home.

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IVviIV key of A major
A - E - F#m - D

The four-chord engine behind a thousand pop hits. The lift from I to V opens the chorus, vi pulls down into feeling, IV walks back toward home.

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IVviIV key of E major
E - B - C#m - A

The four-chord engine behind a thousand pop hits. The lift from I to V opens the chorus, vi pulls down into feeling, IV walks back toward home.

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iVIIIIVII key of B minor
Bm - G - D - A

Heroic minor four-chord. The descent from i to VI to III gives the verse weight, VII slingshots back to the tonic. The Andalusian cousin of the pop axis.

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Songs that feature A

Real records where this chord does structural work. No lyrics quoted, just the title and artist so you can pull up a copy and hear it in context.

Related chords

Chords a step away from the A in the songwriting circle, the natural neighbours when you want a substitution.

Keys where A lives

The keys where this chord turns up diatonically. Open any key page for the full set of progressions that lean on it.

Related references

Other ways to put the A to work across the reference library.

More songwriting tools

Got the chord but still wrestling with the lyric? Find the right rhyme in RhymeForge, or break a writer's block with the unexpected word-pair generator in CollisionLab. Need to map a full progression? The chord builder on the home page is where the A fits into context. All free, no signup.

About the chord builder

The Undercover Zest chord progression builder is a free interactive tool that maps every diatonic and borrowed chord in every key. Click a Roman numeral to hear it, drag chords into a progression, then audition voicings, inversions and tensions until the song clicks.

This page is a static reference for the A. For interactive playback, voice-leading hints and substitution suggestions, open the chord builder above.