A

Q: What notes are in the A chord?

The A chord (A Major) contains: A, C#, E. Its interval structure is shown above in the Theory section.

Q: How do I build A 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 A 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 A?

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.

A Major

Octaves

Musical context

ChordA majorTriad

ArpeggioA majorBroken triad

ScaleA major7 notes

KeyA majorMajor key

ProgressionPop axisSequence

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

Theory

General info

Full name: A Major
Symbol: A
Root: A
Quality: Major

Chord notes

1Aroot

3C#major 3rd

5Eperfect 5th

Functions & resolutions

Typical function in key: VDominant (V)D major
Stability / tension: Stable — can serve as major tonic
Most common resolutions: DD Major EE Major F#mF# Minor
Main resolution: Asource
EE Major
Major chord A is a stable tonic. As tonic it doesn't require resolution, but in a progression context typically moves to IV or V.
Other resolutions: Asource
Deceptive resolution
F#mF# Minor
As the V degree, a major chord can defy expectations by moving to vi instead of I (deceptive cadence).
Asource
Modal resolution
GG Major
In modal context, a major chord can freely move to bVII, bIII, or bVI — characteristic of Mixolydian mode.
Asource
Jazz reharmonization
Amaj7A Major 7
In jazz, a major chord is enriched to maj7, 6/9, or add9 and can smoothly transition into a ii-V of another key (modulation).
Asource
Functional resolution
EE Major
As the IV degree (subdominant), a major chord can resolve to V or directly to I (plagal cadence).

Substitutions

Parallel: AmA Minor
Relative: F#mF# Minor
Mediant: C#mC# Minor

Features

Character: Major, stable
Characteristic interval: Major third (M3)
Description: The major 3rd defines the major quality, while the perfect 5th makes the triad stable.
Application: I, IV, V in major keys
Pop, rock, folk
Cadential chords