A Major
Key Signature
| Property | Value |
|---|---|
| Tonic | A |
| Mode | Major |
| Accidentals | 3 sharps |
| Key Signature Notes | F#, C#, G# |
A major has three sharps (F#, C#, G#) and a bright, clear sound. It is extremely common in popular music and rock, particularly on guitar, and is easily sung by most voices.
Diatonic Chords
The seven diatonic chords of A Major — each built on a scale degree using only the notes of the key signature:
| Degree | Roman Numeral | Chord Type | Chord |
|---|---|---|---|
| 1 | I | Major | A Major |
| 2 | ii | Minor | B Minor |
| 3 | iii | Minor | C# Minor |
| 4 | IV | Major | D Major |
| 5 | V | Major | E Major |
| 6 | vi | Minor | F# Minor |
| 7 | vii° | Diminished | G# Diminished |
Related Keys
- Relative Minor
- F Sharp Minor — shares the same key signature.
- Parallel Minor
- A Minor — same tonic, different key signature.
See all key relationships on the Circle of Fifths.
Scales in A Major
Common scales built from the A tonic:
Transposing Instrument Context
Sharp-key signatures like A Major are comfortable for open-string instruments (guitar, violin). Bb instruments (trumpet, clarinet, tenor saxophone) read in B major to sound A Major. Eb instruments (alto saxophone, Eb clarinet) read in F# major to sound A Major. Standard guitar tuning (E A D G B E) resonates naturally in A Major.