/ Free online tool — BPM detector
Drop a file.
Find the tempo.
The same tempo detection that runs inside Sample Vault, in your browser. No upload. No sign-up.
Click or drop audio.
WAV, MP3, FLAC, OGG, M4A, or AAC.
/ Method
How the BPM detector
works.
Method: onset detection + autocorrelation with grid reconciliation · Built by Sample Vault
The same tempo detection the desktop app runs against your library, in your browser.
/ 01 — Onset tracking
We track where transients land — every kick, snare, and pluck — frame by frame. That gives a list of onsets the tempo detector can lock onto.
/ 02 — Tempo locking
Autocorrelation on the onset envelope finds the period that best repeats. For loops, the file's own length gets cross-checked against common bar counts — that's how a 4-bar loop confidently reports the right BPM rather than a half or double.
/ 03 — Honest failure modes
Atmospheric pads, sustained notes, sparse FX and anything without enough transients return no tempo instead of a confident guess. Low-confidence results are surfaced as estimates, not facts.
/ 04 — Fully local
The file never leaves your machine. Loads once, runs offline thereafter. Useful for unreleased material, label stems, and anything you can't put through a third-party service.
/ Across your library
From one file
to fifty thousand.
Detecting tempo on one file is a party trick. Detecting it on 40,000 files, indexing the result, and letting you pull every 138 BPM loop in F minor with a sub-heavy bass in under a second — that's the desktop app. Same engine, run across every folder you point it at.