Find the Key of Dm7 G7 Cmaj7 (Jazz ii-V-I)
Score the twelve major and twelve minor keys against a list of chord symbols and show the best five.
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About this tool
This page opens the chord key finder preconfigured with the most common cadence in jazz harmony: Dm7, G7, Cmaj7. The tool tests every major and minor key against these three seventh chords the moment the page loads and ranks the candidates by confidence, labelling each chord's scale degree in the winning key — a live result, not a canned illustration.
Dm7-G7-Cmaj7 is the textbook ii-V-I in C major: the minor seventh on the second degree moves to a dominant seventh on the fifth degree, which resolves to a major seventh on the tonic. Almost every jazz standard is built from chains of this three-chord cell transposed to different keys and sometimes shortened to just V-I, which is why recognizing it by ear and by chord symbol is one of the first skills taught in jazz theory.
Replace the three chords with a ii-V-I in another key (for example Em7 A7 Dmaj7 for a ii-V-I in D major) to see the same pattern of degrees repeat, or paste in a longer excerpt from a lead sheet to find the key of an entire tune section.
Example. C Am F G ranks 1. C major - 96%, with C as I tonic, Am as vi submediant, F as IV subdominant, and G as V dominant. A minor is second at 88%. In G major, F is marked outside key.
Limit. Only major and natural minor are scored, and only the top five are shown. The page reads chord symbols. It does not detect a key from audio.