Guitar Chords in the Key of G Major

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

The chords in the key of G Major are G Major, A minor, B minor, C Major, D Major, E minor, and F♯ 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.