Free Audio Chord Finder

Worked example

Press "Try a sample (C – Am – F – G)". It builds a 16-second test recording in your browser: the chords C, Am, F and G for 2 seconds each, played twice, so the right answer is known in advance. At the default "Simple (fewer changes)" setting the tool makes one decision about every 0.74 seconds, and at "Detailed" about every 0.37 seconds. Set Transpose to +2 and the progression C – Am – F – G reads D – Bm – G – A. Tick "Use flats (B♭ not A♯)", set Transpose to +1, and it reads Db – Bbm – Gb – Ab. "Copy chord sheet" gives one line per change, such as "0:00 C" (minutes and seconds, two spaces, the chord), and "Download .txt" saves it as "sample-chords-C-Am-F-G-chords.txt".

Which settings to use, and the limits

• Start with "Simple (fewer changes)". "Detail" is set to "Simple (fewer changes)" by default. It decides about every 0.74 seconds and is strict about switching chords, which gives a readable list for a song. "Detailed" decides about every 0.37 seconds with a lower penalty for switching, so it follows quick changes but can also list short, spurious chords. Switch between them and the list updates without analyzing the file again.
• Turn "Include 7th chords" off for plain songs. With "Include 7th chords" ticked (the default) the tool can name major, minor, dominant 7th (G7) and minor 7th (Em7) chords. A 7th has to match clearly better than the plain chord to be chosen. Unticked, it only chooses major and minor. It does not name diminished, augmented, suspended or slash chords.
• Transpose to suit your instrument or voice. "Transpose" moves every chord, the key and the chord sheet from -11 to +11 semitones using the − and + buttons. "Use flats (B♭ not A♯)" switches the spelling of the black-key notes. This changes the names only; the audio you hear does not change.
• Follow the timeline while it plays. The large "Chord" box shows the chord at the playhead and "Next:" shows the one after. Click any line in the list to jump there and play. "Chords in this song" lists each different chord once, in order of first use, and "Key" shows the key estimated from the whole song, such as "C major".
• Copy or save the chord sheet. "Copy chord sheet" copies plain text with one line per chord change. "Download .txt" saves the same lines as "name-chords.txt", with the song name and key on the first line. Both use the current Transpose, flats, 7th chords and Detail settings.
• Know the limits and what works best. One file at a time, up to 20 minutes long; longer songs have to be trimmed first. It accepts MP3, M4A, WAV, FLAC, OGG, AAC, Opus and the sound of MP4, MOV or WebM videos, as far as your browser can decode them. The song is mixed to mono and analyzed between 60 Hz and 2 kHz. There is no AI model, only a note analysis, and the song is analyzed in your browser and not uploaded. Clear guitar, piano and band recordings work best.

Common problems and how to fix them

It says "song.mp3 could not be read as audio."

The tool uses your browser's own audio decoder, with no fallback for formats it cannot read. The file may be damaged, or its codec may not be supported by your browser. Try the original file, or save it as MP3 or WAV first. A video needs a sound track the browser can play.

It says "song.mp3 is longer than 20 minutes. Trim it first."

The limit is 20 minutes of audio. Cut the part you want, such as one song out of a long recording, with an audio trimmer and add that file.

The chords flicker, or there are far too many changes.

Set "Detail" to "Simple (fewer changes)" and untick "Include 7th chords". Distorted guitars, drums-only passages and busy jazz harmony are harder for this method, as the note on the page says.

Some parts show "N.C." instead of a chord.

"N.C." means no chord. It is used for very quiet passages (less than 3 percent of the level of the loudest part) and for sounds with no clear notes, such as drums alone or noise. A fade-out or a silent gap will show it.

The key is missing or looks wrong.

The key only appears once at least one chord has been found. It is an estimate from all the notes in the song, and a major key and its relative minor use the same notes, so they are easy to confuse. Check it against the chords in "Chords in this song" before relying on it.

How it compares

This tool works out chords from the notes it hears, with no AI model. That means no model to download, but it only knows four chord types and does not hear the bass note, so inversions and slash chords are not named. Its changes fall on blocks of about 0.74 or 0.37 seconds, not on the beat. Working out chords by ear, or using a published chord chart for the song, is more accurate when you have the time, and the result here is best used as a starting point to check against your ears. Its advantage is that it works on any recording you have, with the key and a transposable sheet.