Chords.fm

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Practice Tools

Drop in an mp3 to slow it down without changing pitch, set a loop on the tricky part, transpose for any instrument. Everything runs in your browser — we never see your audio.

With Pro

Want chord charts and lyrics for this song?

Chords.fm transcribes the chord progression and time-aligned lyrics from the same audio. Free tier available.

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How accurate is it?

Tempo and pitch processing use SoundTouchJS; key + BPM detection runs through Essentia. Both are good on clean recordings and most pop / rock tracks; tempo detection can occasionally land on a half- or double-time multiple, and key may show a relative major / minor on ambiguous material. The slow-down + loop combination is what most musicians actually use this for — those are rock-solid.