I
Major
Tonic.
Diatonic chords
See the chord family that belongs to a key.
Diatonic chords are built from notes inside a scale. In a major key, the familiar pattern of chord qualities makes it easier to predict progressions and function.
diatonic chordschords in a keydiatonic chords major scalemajor key chordsroman numeral chords
Major key
Seven scale degrees produce a repeating quality pattern.
Build a triad on each scale degree using only notes from the key.
ii
Minor
Predominant.
iii
Minor
Mediant.
IV
Major
Predominant.
V
Major
Dominant.
vi
Minor
Relative minor / tonic family.
vii°
Diminished
Leading-tone function.
Roman numerals
Describe scale degree and chord quality.
Uppercase commonly indicates major, lowercase minor, and symbols mark diminished quality.
I, IV, V
Major
Uppercase.
ii, iii, vi
Minor
Lowercase.
vii°
Diminished
Degree symbol marks diminished triad.
Minor key
Minor harmony has several common forms.
Natural, harmonic and melodic minor can affect diatonic chord qualities, especially the dominant.
Natural minor
Baseline
Provides the relative-major collection.
Harmonic minor
Raised 7th
Creates a major V / dominant 7.
Melodic minor
Raised 6th and 7th ascending
Adds another source of functional and modal color.
FAQ
Quick answers about diatonic chords.
Use these answers as a reference, then explore the relationships interactively.
What are diatonic chords?
Chords built only from the notes of a given scale or key.
What are the diatonic triads in a major key?
I major, ii minor, iii minor, IV major, V major, vi minor and vii diminished.
Why are Roman numerals useful for diatonic chords?
They show scale degree and chord quality independently of the key, making progressions easier to compare and transpose.
ChordRevelation
Move from explanation to interactive harmony.
Change the key, compare voicings, follow voice leading and see the same idea directly on the fretboard.