MusicReasonChords and Harmony
Where does this progression end, harmonically?
Enter a short chord progression and its key. This tool flags indexed cadence candidates, the preceding and following harmonic functions around each one, and an explanatory strength label. "Strength" here is a rule label, not a listener-proven rating.
Answer
Want to learn more? Chord Function, Cadence, and Substitution
Understand
A cadence is a named ending pattern between two adjacent (or, for ii-V-I, three consecutive) chords in a stated key. This tool looks only for the sequence patterns its rule set names explicitly, after mapping each chord to a numeral in the stated key first; it never infers a cadence from a chord pair the key mapping cannot classify as diatonic.
Worked examples
Dm7 to G7 to C in the key of C major flags an ii-V-I candidate spanning all three chords, the strongest-labeled pattern in the rule set. G7 to Am in the same key flags a deceptive candidate, since the dominant resolves to the relative minor's submediant rather than the tonic. A chord pair ending on the dominant with no further resolution shown flags as a half cadence instead.
Method and limitations
Every chord is classified against the stated key's diatonic degree table first. The tool then checks each adjacent pair for the authentic (V-I), plagal (IV-I), half (ending on V), and deceptive (V-vi) patterns, and separately checks every three consecutive chords for the named ii-V-I pattern. A cadence at a genuine phrase boundary in real music can span more surrounding context than this bounded rule set inspects, and a chord pair that happens to match a pattern's numerals without being a true phrase ending is a known false- positive risk this tool does not attempt to filter by listening.
A single progression can flag more than one overlapping candidate, and that is expected rather than an error: a three-chord ii-V-I also contains its own final V-I pair as an authentic cadence in its own right, so both appear in the result. This tool does not merge overlapping candidates into a single "best" answer, since a reader may want to see either the shorter, more local pattern or the longer, fuller one depending on what they are studying.