Chords in Eb major

Eb major is built from the notes Eb, F, G, Ab, Bb, C and D. Its scale carries 3 flats. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on Eb as the I. The chord on the fifth degree is Bb, a major V, so Eb major has the leading tone that makes a Bb-to-Eb cadence sound final.

Beyond those seven, Eb major commonly borrows Ebm (i), Fdim (iiø), Gb (bIII), Abm (iv) and Bbm (v) from the parallel minor — the mixture chords that give a progression somewhere unexpected to go.