Chords in a key
Pick a key to see the seven chords built on its scale, with Roman numerals and notes. Tap a chord to see it on the keyboard.
Chords in C major
Scale: C D E F G A B
Key signature: no sharps or flats.
How the pattern works
Stack thirds on each note of a scale, using only notes from that scale, and you get seven triads. Their qualities follow the same pattern in every key (Open Music Theory notes this is why memorizing them is useful):
- Major keys: I, ii, iii, IV, V, vi, vii° (major, minor, minor, major, major, minor, diminished).
- Minor keys (natural minor): i, ii°, III, iv, v, VI, VII.
- Seventh chords in major: Imaj7, ii7, iii7, IVmaj7, V7, vi7, viiø7.
Uppercase numerals are major chords, lowercase are minor, ° means diminished, + means augmented and ø means half-diminished. Minor key signatures are based on the natural minor scale; the harmonic minor table shows the common raised 7th.
References: Chelsey Hamm, “Triads,” Open Music Theory (VIVA Pressbooks); Chelsey Hamm and Bryn Hughes, “Minor Scales, Scale Degrees, and Key Signatures,” Open Music Theory; “Seventh Chords,” Open Music Theory (VIVA Pressbooks).