Song Key Finder from Chords
Type at least two chord symbols to rank possible major and minor keys. This tool does not listen to, identify or upload audio. It parses chord roots and basic major, minor or diminished quality, ignores slash-bass notes and most extensions, and compares the result with diatonic triads. The displayed percentage is a relative match score, not statistical confidence.
What the analyzer reads
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1
Enter chord symbols
Spaces, commas, bars and line breaks work; at most 24 recognized chords are used.
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2
Choose major, minor or both
The preference filters the candidate modes rather than detecting mood.
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3
Compare candidates
Review Roman numerals, diatonic matches and outside chords; use melody and cadence to resolve ambiguity.
Algorithm and limits
Each recognized chord receives a pitch class and basic quality. Every candidate major or natural-minor key gains points for diatonic chords, tonic appearances and a tonic final chord. In minor, a major dominant is also accepted. The best raw score is scaled to 96%, and other candidates are shown relative to it, so the percentage is not a measured probability.
Enharmonic input such as C♯ and D♭ shares a pitch class. Results use conventional flat spellings for major candidates and common sharp spellings for minor candidates. Slash bass notes are discarded; sevenths, added tones and suspensions are reduced to a basic triad interpretation. Modes beyond major/minor, melody, rhythm, inversions, borrowed harmony, modulation and cadence context are not fully modeled. Open Music Theory explains diatonic triads and Roman numerals and why chromatic chords can require contextual analysis.
Typed chords are processed on the server through Livewire. Funnel mode also puts them in the URL, which may enter browser history and server logs. The tool accepts no audio or file input.
Frequently Asked Questions
No. It only analyzes typed chord symbols.
It is the candidate score relative to the best score for this input, not statistical confidence.
Relative keys, short loops, borrowed chords and missing melody or cadence can make the tonal center ambiguous.
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