Chord Progression Generator
Generate chord progressions in any key and mode: classic loops or seeded random ideas, with Roman numerals, note spellings and playback.
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- Roman numerals
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- Chords
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Your browser blocked or does not support the Web Audio API, so playback is unavailable here. Everything else on this page still works.
Diatonic chords in this key
| Degree | Numeral | Chord | Notes |
|---|
How it works
Every progression here is written as Roman numerals over the key you pick. The seven scale
degrees come from the major scale (0 2 4 5 7 9 11 semitones) or the natural minor
scale (0 2 3 5 7 8 10), so in C major degree 5 is G and in A minor degree 7 is G.
Case carries the chord quality the way it does in a theory textbook: uppercase is major
(I, IV, V), lowercase is minor (ii,
vi), ° is diminished, ø7 is half-diminished and a
flat prefix lowers the degree by a semitone (♭VII in C is B♭). Numerals in
minor keys are read against the natural minor scale, which is why the minor pop loop
i–VI–III–VII in A minor gives Am–F–C–G, while an
uppercase V in a minor key is the borrowed harmonic-minor dominant (E major in A
minor).
Notes are spelled by scale degree rather than by pitch number, so you get the letters you would
actually write on a stave: the V of A minor comes out as E G♯ B, not
E A♭ B. Pick one of the classic progressions — the four-chord axis loop, the
50s doo-wop turnaround, the jazz ii–V–I, the twelve-bar blues, the Andalusian cadence
— or switch to Random, which walks a small chord-transition table (I likes
going to IV, V, vi or ii; V likes resolving to I) and always finishes on a chord that leads back
to the tonic so the loop repeats cleanly. The random generator is seeded: the same seed always
produces the same progression, and you can share it with ?seed=yourseed in the URL.
Playback uses the Web Audio API to sound one bar per chord at the tempo you set. Everything runs in your browser with plain JavaScript — nothing is uploaded, there is no sign-up and there are no ads.
Frequently asked questions
What chords are in a I–V–vi–IV progression?
It depends on the key. In C major the four-chord axis loop is C – G – Am – F; in G major it is G – D – Em – C; in D major it is D – A – Bm – G. Pick a key at the top of the page and the Roman numerals are converted for you, complete with the notes in every chord.
How do Roman numerals work in a minor key?
Numerals in minor keys are read against the natural minor scale (0 2 3 5 7 8 10 semitones), so in A minor i is Am, III is C and VII is G. Uppercase means major, lowercase minor, ° is diminished and ø7 is half-diminished. An uppercase V in a minor key is the borrowed harmonic-minor dominant, E major (E G♯ B) in A minor rather than the natural Em.
Is the random progression generator repeatable?
Yes. Random mode is seeded: the same seed always produces exactly the same progression, and you can share it by adding ?seed=yourseed to the page URL. The generator walks a small chord-transition table and always ends on a chord that leads back to the tonic, so the loop repeats cleanly.