Chord · A Major (1st Inversion)
A/3 Chord
A/3 is C#, E and A — major triad with the third in the bass.
A/3 on every instrument
The same 3 notes, 1 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.
What A/3 is made of
A Major (1st Inversion) (A major (1st inversion)) is built from the notes C#, E, A, with the interval pattern 3, 5, 1. A common major (1st inversion) chord across many styles.
Stack 3, 5 and 1 on a root of A and you get C#, E and A. That interval recipe is what makes the chord a major first inversion chord — move the same shape to another root and the character travels with it, which is why E/3 sounds like a transposed A/3.
Major (1st Inversion): Major triad with the third in the bass.
Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with C♯ rather than its enharmonic equivalent.
Keys that contain A/3
All 3 notes sit inside the scale of 6 keys. The roman numeral marks the degree the chord is rooted on.
Other chords on A
Same root, different colour.
The same major first inversion shape, moved
The identical interval recipe, built on other roots.
Questions people ask about A/3
- What notes are in the A/3 chord?
- A/3 is made of C#, E and A — the 3, 5 and 1 degrees of a major first inversion chord built on A.
- What keys use the A/3 chord?
- Every note of A/3 belongs to 6 keys: D Major (V), A Major (I), E Major (IV), B Minor (VII), F# Minor (III), C# Minor (VI). The roman numeral is the scale degree the chord is rooted on.
- How do you play A/3 on guitar and piano?
- This page shows A/3 on piano — 1 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.
Learn the theory behind it
Why A/3 behaves the way it does — the guides that explain the chord instead of just spelling it.