Key of A Major

Everything the key of A major contains: its scale, its seven diatonic chords, and its closest relatives.

The key of A major is built on the A major scale. Harmonizing that scale in thirds yields its seven diatonic chords: A – Bm – C#m – D – E – F#m – G#°. Its relative minor — the key sharing exactly the same notes — is F# minor, and its parallel minor is A minor.