Chord Finder for Songs: Chords and Fingerings from Audio

It reads harmony straight off the audio rather than transcribing notes first, which is what lets it work on a dense mix where a note-by-note approach falls apart. A song with clear chordal instruments — guitar, piano, organ — and a steady arrangement comes out reliably. What defeats it is harmony that is implied rather than played: a bass line and a voice with nothing filling the middle, a solo instrument, a track where the chord changes under a held note. Heavy distortion is the other hard case, because it adds harmonics that look like notes that are not being played. When the reading is uncertain, that is shown rather than smoothed over — a wrong chord presented confidently costs more time than an admitted gap.

They are generated, not looked up: the tool searches the fretboard and keeps only positions one hand can actually hold — a span of no more than four frets, no more than four fingers, a barre with nothing fretted under it, and no muted string between two ringing ones. That is why a diagram exists for a rare chord and for a non-standard tuning, not only for the ones that made it into a chord book.

It turns sevenths, diminished and suspended chords into plain triads: Am7 becomes Am, G7 becomes G. The third is always kept, so major never turns into minor and the song stays itself. Neighbouring bars that become identical are merged, so nothing reads as a chord change where there is none.

Simpler chords get a small advantage on an equal match: a four-note template absorbs a passing tone or a reverb tail more easily, and without that margin sevenths would systematically win contaminated frames. When measured, a plain triad was read as a seventh in exactly the places where no seventh was sounding.

Because Csus2 is C-D-G and Gsus4 is G-C-D — the same three pitch classes. Only the bass tells them apart, and a chromagram discards register and voicing by construction. Offering both would mean printing a coin toss, so such chords are named sus4.

It shows the chord shapes you actually hold with the capo on. A capo at the 2nd fret means what you hold sounds two semitones higher, so the chart is recalculated downwards and a bar appears at the nut of the diagram.

That the top two candidates were close there and the choice between them is unreliable. Usually transitions, pauses, or places where the harmony is implied rather than sounded.

Decoding, harmonic analysis and the fingering search all run in your browser through WebAssembly — on your own device, with nothing to install. It keeps working offline once the page has loaded.