The chord progression generator above takes a progression written in roman numerals, puts it into whichever key you choose, and spells every chord correctly for that key. It also labels each chord's harmonic function, offers diatonic sevenths, and can tonicise the final chord with a secondary dominant. It is a transposition and notation tool, not a composition engine, and it is deliberately built that way.
Arb Digital builds free calculators that get their reference material right and say where it comes from. The theory implemented here is common-practice diatonic harmony as set out in Open Music Theory, an open-access textbook, and every quality and function label below is traceable to it rather than to a guess.
What This Chord Progression Generator Does
Pick a key and a mode, and the calculator builds the diatonic scale with correct letter names — each of the seven letters used exactly once, with whatever accidental that requires. It then builds the diatonic triad or seventh chord on each degree, applies your chosen progression, and prints the result three ways: as chord symbols, as roman numerals, and as a line of harmonic functions.
Two optional modifications are available. Diatonic sevenths add the seventh above each root, giving major sevenths, minor sevenths, a dominant seventh and a half-diminished chord in their proper places. The secondary dominant option replaces the second-to-last chord with the dominant seventh built a perfect fifth above the final chord, which is the standard way of making a non-tonic chord feel like a temporary destination.
In minor keys there is a third option. Natural minor gives a minor v, which does not pull towards the tonic. Raising the seventh degree inside that chord produces a major V, which does — and that is why most minor-key music is written with a raised leading note at cadences even though the key signature does not contain one. The raise is applied to the dominant alone, because a subtonic VII chord elsewhere in a progression is normally left unraised.
How This Differs From Our Chord Calculator
Our live chord calculator handles one chord in depth. You give it a root, a quality from power chords through extended and altered chords, an octave and an inversion, and it returns the notes, the semitone intervals from the root, a voicing with octave tags for a keyboard player, and the root frequency at a tuning reference you set. It is a single-chord tool.
This page never looks inside a chord at that level and never touches frequencies. Its unit is the sequence: which chords follow which, what those chords are called in a given key, and what role each plays. The two are complements — generate a progression here, then take any individual chord to that page if you need its exact voicing.
How the Chords Are Worked Out
Three steps, all mechanical.
First, the scale. A major scale is the semitone pattern 0-2-4-5-7-9-11 above the tonic; natural minor is 0-2-3-5-7-8-10. The spelling comes from a separate rule: the seven letter names are used in order starting from the tonic's letter, and whatever accidental is needed to hit the right pitch is applied. That is why F♯ major contains E♯ rather than F, and why the scale is readable rather than merely correct in pitch.
Second, the chords. A triad stacks the first, third and fifth scale degrees above each root, counting within the scale. Open Music Theory's chapter on triads and seventh chords gives the four qualities that result: major is a major third and perfect fifth above the root, minor a minor third and perfect fifth, diminished a minor third and diminished fifth, and augmented a major third and augmented fifth. In a major key this produces major triads on I, IV and V, minor on ii, iii and vi, and a diminished triad on vii. In natural minor it produces minor on i, iv and v, major on III, VI and VII, and diminished on ii.
Third, the function labels. Open Music Theory's chapter on harmonic functions organises common-practice harmony into tonic, subdominant and dominant categories according to which scale degrees a chord contains, and describes function as the role a chord plays in creating a larger progression. The labels shown here follow that grouping.
Work an example through. In C major, I–V–vi–IV gives C – G – Am – F, functioning as tonic, dominant, tonic, subdominant. Switch to diatonic sevenths and it becomes Cmaj7 – G7 – Am7 – Fmaj7. Apply the secondary dominant and the Am is replaced by C7, the dominant seventh a fifth above F, giving C – G – C7 – F, with the third chord labelled V7/IV.
Why Roman Numerals Beat Chord Names
Roman numerals feel like an academic complication until the first time you have to move a song. Then they become the only sensible way to hold a progression in your head.
A progression is a pattern of relationships between scale degrees. C–G–Am–F and D–A–Bm–G are the same progression; the letters are an accident of key. Learn it as I–V–vi–IV and you know it in all twelve keys at once, which is exactly what a singer asking you to take it down a tone is relying on.
The notation carries quality as well as position. Upper case is a major triad, lower case minor, a small circle after a lower-case numeral is diminished, and a slashed circle is half-diminished. So vii° in a major key is telling you two things at once: the chord sits on the seventh degree, and it is diminished. If you need to move actual written material rather than a progression, our music transposer does that job, and the music scale generator produces the underlying scales in any key and mode.
What the Progressions in the List Are Doing
Most of the patterns offered are variations on a small number of moves, and knowing which move you are looking at is more useful than memorising the list.
The strongest is the descending fifth, where each root falls a fifth to the next: ii–V–I is the classic case, and Pachelbel's sequence is an extended version of the same idea. It works because the root motion mirrors the dominant-to-tonic relationship, so each chord arrives as though resolved.
The second is the tonic-and-back pattern of I–V–vi–IV and its rotations. What makes it so durable is the vi: it is a tonic-function chord, so the progression never really leaves home, which is why it can loop indefinitely without demanding a cadence.
The third is modal borrowing, most audibly the ♭VII chord. In a major key it is not diatonic at all — it comes from the parallel Mixolydian mode — and it is a large part of why so much rock harmony does not sound like common-practice classical harmony despite using the same triads.
The twelve-bar blues sits outside all of this. Its I, IV and V are usually all dominant sevenths, which is not diatonic to any single major key, and trying to analyse it in functional terms misses the point of it.
Where a Generator Stops Being Useful
A progression is a small part of what makes music work, and it is worth being clear about what this page cannot give you.
Voice leading is the largest omission. The same four chords sound completely different depending on how they are voiced and how the individual lines move between them. Smooth voice leading — keeping common tones and moving the rest by step — is most of the difference between a progression that sounds composed and one that sounds like a chord chart.
Rhythm and harmonic rhythm come next. How long each chord lasts, and whether changes fall on strong or weak beats, changes the character of a progression more than substituting a chord does. Our BPM calculator handles the tempo side of that.
Finally, melody. A progression is scaffolding, and the same scaffolding supports very different songs. If you need pitch material rather than harmony, the music interval calculator works interval relationships, the harmonic series calculator covers the overtone side, and the note frequency converter gives actual frequencies — this page deals in pitch-class names only, so tuning and temperament never arise in it.
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Browse the Free Tools Hub Talk to Arb DigitalCommon Mistakes to Avoid
- Memorising letters instead of numerals. C–G–Am–F is one key's version of I–V–vi–IV. Learn the numerals and you have it in every key.
- Spelling chords enharmonically. D♯ and E♭ are the same pitch and not the same chord name. Using the wrong one makes written music much harder to read.
- Expecting a minor v to cadence. Natural minor has no leading note, so v does not pull to i. That is what the harmonic minor option is for.
- Treating the blues as diatonic. Its I, IV and V are typically all dominant sevenths, which belong to no single major key. Functional analysis does not describe it well.
- Assuming the progression is the song. Voice leading, harmonic rhythm and melody do more work than the chord choices do.
Related Free Tools From Arb Digital
For a single chord's notes, intervals, voicing and root frequency, use the chord calculator. Build the underlying scales with the music scale generator, move written material with the music transposer, and work interval relationships with the music interval calculator. The note frequency converter and harmonic series calculator cover pitch and overtones, and the BPM calculator handles tempo. Everything else is on the free online tools hub.
Frequently Asked Questions
It is a four-chord pattern built on the first, fifth, sixth and fourth degrees of a major scale, giving a major, major, minor and major chord. In C major it is C, G, Am and F. It loops well because the vi is a tonic-function chord, so the progression never really leaves home and never demands a cadence.
Because a progression is a pattern of scale degrees rather than a fixed set of letters. C-G-Am-F and D-A-Bm-G are the same progression in different keys. Written as I-V-vi-IV it is one thing you know in all twelve keys, which is what transposing on the spot depends on.
Upper case indicates a major triad and lower case a minor one. A small circle after a lower-case numeral marks a diminished triad, and a slashed circle marks a half-diminished seventh chord. So vii degrees in a major key tells you both the scale degree and the quality at once.
It is a dominant seventh chord built a perfect fifth above a chord that is not the tonic, used to make that chord briefly feel like a destination. In C major, the secondary dominant of F is C7, written V7/IV. The substitution option here applies exactly that to the second-to-last chord.
Because natural minor has no leading note, so its v is minor and does not pull strongly to the tonic. Raising the seventh degree by a semitone makes the V major, restoring that pull. This is why most minor-key cadences are written with a raised seventh even though the key signature does not include it.
Major triads on the first, fourth and fifth degrees, minor triads on the second, third and sixth, and a diminished triad on the seventh. With sevenths added they become major sevenths on I and IV, minor sevenths on ii, iii and vi, a dominant seventh on V and a half-diminished seventh on vii.
That tool handles one chord in depth, returning its notes, semitone intervals, a voicing with octave tags and the root frequency at a tuning you set. This page works with sequences instead: which chords follow which, what they are called in a given key, and what function each serves. It never touches frequencies.
This page implements common-practice diatonic harmony as set out in the open-access textbook it cites. Music theory describes conventions rather than rules, and plenty of excellent music departs from every pattern listed here.
