MusicReasonProgression, Transposition, and Arranging
What are the Roman numerals for this progression?
Type a chord progression and a key. This tool labels every chord in sequence with a Roman numeral, using the surrounding chords to identify applied dominants, without implying it can detect the key from the chords alone.
Answer
Your progression text stays in your browser and is never logged, stored, or sent anywhere.
Want to learn more? Chord Function, Cadence, and Substitution
Understand
This tool never implies a key detector: the key is a declared input, not a guess derived from the chords. Sequence context is used only for a bounded applied-dominant check (a dominant-quality chord a fifth above the following chord), not a full stylistic analysis.
Worked example
C, Am, F, G in the key of C major maps to I - vi - IV - V. D7 followed by G in the same key shows V7/V - V: the D7 is read as an applied dominant preparing the following G (the plain diatonic V), not as a diatonic ii chord.
Method and limitations
Each token is parsed into root, quality, and bass, then compared against the declared key's diatonic degrees; an unmatched chord is checked against a following chord for an applied-dominant relationship before falling back to an ambiguous state. This tool supports up to 32 chords and does not invent a key context beyond what you declare.