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The A7 chord

Built from A - C# - E - G, the A7 is a dominant seventh that sounds the cornerstone of the twelve-bar. It lives at the centre of every blues form and most jazz tunes, and it shows up in more songs than you would expect. Sits perfectly under a Texas-blues groove, and the V chord in D-major country. What follows below: the voicings worth memorising on guitar and piano, the theory in plain language, progressions in two or three different keys, and a short list of real records that lean on the chord.

Hear the A7 in the chord builder →
Scale degrees Note names

Voicings for A7

Common ways to grip the A7 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 A7 across the neck. Pick the shape closest to where your hand already sits.

Guitar: E7 shape at fr.5
Notes: A - C# - E - G (chord tones)
Guitar: A7 shape at fr.2
Notes: A - C# - E - G (chord tones)
Guitar: D7 shape at fr.7
Notes: A - C# - E - G (chord tones)
Guitar: C7 shape at fr.9
Notes: A - C# - E - G (chord tones)
Guitar: G7 shape at fr.2
Notes: A - C# - E - G (chord tones)
Guitar: top-4 voicing
Notes: A - C# - E - G (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.3
Notes: top-string triad, fr.3
Triad: top strings (G-B-e) · fr.8
Notes: top-string triad, fr.8
Triad: middle strings (D-G-B) · open
Notes: middle-string triad, open
Triad: middle strings (D-G-B) · fr.5
Notes: middle-string triad, fr.5
Triad: middle strings (D-G-B) · fr.8
Notes: middle-string triad, fr.8
Triad: bass strings (A-D-G) · open
Notes: bass-side triad, open
Triad: bass strings (A-D-G) · fr.5
Notes: bass-side triad, fr.5
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 - G. Root A at the bottom. The classic stacked-thirds spelling of a dominant seventh.
Piano: first inversion
Notes: C# - E - G - A. C# at the bottom. Common in chord-melody, walking bass lines and gentler voicings.
Piano: second inversion
Notes: E - G - A - C#. E at the bottom. A floating, suspended feel often used in hymns and ballads.
Piano: third inversion
Notes: G - A - C# - E. G at the bottom. The seventh in the bass , a smooth jazz favourite.

The theory behind A7

A7 is a dominant seventh built on A. Its three or four notes (A - C# - E - G) sit a specific distance apart: root, major third, perfect fifth, minor seventh. That makes it a passing chord in the key of a closely related major key, and the same chord works as the passing chord in a closely related major key. The simplest rule of thumb: the A7 wants to resolve down a fifth to the next chord.

Progressions that use A7

Short progressions that put the A7 to work. Each one is shown in a different key so you can pick the one that suits your singer.

IIVV key of C major
A7 (as passing colour)

This chord appears as a borrowed or passing chord in many major-key progressions.

→ Build this in the chord builder

Songs that feature A7

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 A7 in the songwriting circle, the natural neighbours when you want a substitution.

Keys where A7 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 A7 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 A7 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 A7. For interactive playback, voice-leading hints and substitution suggestions, open the chord builder above.