A tied score stays tied
Several keys can contain the same short set of chords. The result lists tied major-key candidates instead of inventing certainty from chord membership alone.
Question marks preserve the chromatic evidence
A chord outside the selected major-key triads remains visible as a question mark. The analyzer does not silently rename it, discard it, or force it into a diatonic role.
The cadence check uses order, not just inventory
The final two analyzed chords are inspected for dominant-to-tonic motion. The same chord collection in another order can therefore produce a different cadence note.
Questions
These answers define the scope of automatic harmonic analysis.
Does the top candidate prove the song key?
No. Melody, phrase endings, duration, inversions, and borrowed harmony can change the interpretation.
Which chord symbols are supported?
Basic letter roots with sharps or flats and common minor or diminished suffixes work best.
Why are Roman numerals useful?
They describe a chord root and quality relative to a candidate key, allowing the pattern to be compared across keys.
Sources behind the method
The tool combines published music-theory definitions with formulas exposed directly in its result.
Calculations and microphone analysis run locally in this browser.