BigBadBird

BPM & Key Detector

Drop a track and read its tempo and key in seconds. Free, no sign-up, and your audio never leaves your browser.

How to use the BPM & Key Detector

  1. Drop your audio file

    Choose an MP3, WAV, M4A, OGG, or FLAC file up to 50MB. It is analyzed in your browser, so nothing uploads.

  2. Read the tempo and key

    The detector shows the BPM with a confidence rating, plus the musical key and scale of the track.

  3. Copy the result

    Copy the tempo and key for your setlist, DJ prep, or a collaboration brief.

Frequently asked questions

How accurate is the BPM detection?

The detector uses a multi-feature beat tracker and reports a confidence rating with each result. Steady four-on-the-floor tracks read most reliably; live or rubato recordings can vary.

Does my audio get uploaded?

No. The file is analyzed entirely in your browser, so your audio never leaves your device.

Can it detect the musical key?

Yes. Alongside the tempo, it estimates the key and whether the track is major or minor.

What can I do with the tempo and key?

Use them to prep a DJ set, match tracks for a mashup, or brief a collaborator. Feed the tempo of each song into the Setlist Architect to build an energy arc across your show, or turn the same track into a beat-locked clip with the Music Visualizer.

Is it free?

Yes. There is no sign-up, no watermark, and no limit on the number of tracks you check.

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