Guitar Chords in the Key of B Flat (B♭) Major

The chord formula for any Major key is Major, minor, minor, Major, Major, minor, diminished.

The chords in the key of B flat (B♭) Major are B♭ Major, C minor, D minor, E♭ Major, F Major, G minor, and A diminished.

A common way to number these chords is by Roman numerals: I, ii, iii, IV, V, vi, vii. Numerals that represent a major chord are usually capitalized, and minor and diminished chords are lower case.