The chord formula for any Major key is Major, minor, minor, Major, Major, minor, diminished.
The chords in the key of D Major are D Major, E minor, F♯ minor, G Major, A Major, B minor, and C♯ 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.
