Key of C Major

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

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