# Free MP3/WAV BPM finder

Canonical: https://phasevoid.com/tools/bpm-detector/

The free MP3/WAV BPM finder analyzes an 8–60 second section locally and silently, shows ranked tempo alternatives and half/double-time choices, and transfers the selected track to Studio only after explicit receipt. Find tempo in Studio reuses the loaded file. Apply tempo changes BPM only; it does not start sound, align beat one, change playback speed or compensate physical latency. No file, waveform, filename or tempo-analysis result is uploaded or cached by this tool.

## Use it

1. Choose a file up to 200 MB. Select a steady 8–60 second section.
2. Analyze and compare candidates; Club (70–200) favors approximately 135 BPM, while Wide (40–300), Slow (40–120) and Fast (120–260) use no such preference. Half/double or typed corrections are manual choices.
3. Use track & tempo in Studio, keep this tab open and Receive selected track. It arrives paused. Review and Apply separately.
4. Choose the intended pulse source, then Tap/Resync on a beat. BPM adoption preserves the current beat position and rearms the interval; it does not set beat one.

Already loaded a track? Sound → Timing & beat sync → Find tempo from loaded track reuses it. Apply/Undo require stopped recording, render, sequence, Auto scene, mix, Room mode and transitions. Undo restores the previous BPM unless the file/timing changed.

## Limits and privacy

This worker uses spectral onset changes and periodicity of the louder stereo channel. No whole-track tempo map, beat/downbeat detection, pitch/key estimate, stretching or physical latency correction. Several plausible pulses indicates competing candidates; no clear pulse means try another section or use manual Tap. A candidate is not a confidence probability. Files, waveforms and results are not uploaded or cached by this tool. Explicit same-origin tab receipt transfers the selected File only in-browser.

Method background: [Ellis 2007](https://www.ee.columbia.edu/~dpwe/pubs/Ellis07-beattrack.pdf), not a claim to implement its full tracker. [Dated first-party checks](https://phasevoid.com/evidence/tempo-finder-2026-10-15.json), not a representative-dataset accuracy or physical synchronization claim.

[Prepare live visuals](https://phasevoid.com/guides/live-visuals/#beat-sync) · [Render a film](https://phasevoid.com/guides/youtube-visualizer/#file-render).


## Align the file beat grid

Sound → Timing & beat sync → Align file beat grid decodes a 2–32 second waveform window locally and silently. The operator places beat one, enters 30–300 BPM, inspects later windows for drift and deliberately applies BPM, file alignment and Track sync. Guarded Undo restores the earlier BPM, exact file phase and pulse source. Track sync and file-render reviews/films use the same pulse envelope at absolute soundtrack seconds, including trimmed starts and pulse delay. A different soundtrack cannot borrow the loaded file’s grid. Audio, playback, cue-grid position, mapping and delay stay separate. Alignment lasts in this tab for this file; replacement, session load and reload reset it. No changing tempo map, automatic downbeat detection, audio stretching or physical latency correction. [Full workflow](https://phasevoid.com/guides/music-visualizer/#file-beat-grid).