BPM (Beats Per Minute) is the unit of measurement for musical tempo — how many beats occur per minute. 120 BPM means 2 beats per second. It is fundamental for syncing loops in music production, aligning video cuts to music, configuring delay and arpeggiators in synthesizers, and beatmatching in DJing.
BPM Detector
Detect the BPM (tempo) of music and beats using autocorrelation — or use Tap Tempo for manual measurement.
How autocorrelation-based BPM detection works
BPM (Beats Per Minute) measures musical tempo — how many beats occur per minute. Automatic detection in this tool uses energy autocorrelation: audio is converted to mono, downsampled to ~4 kHz (efficient and sufficient for beat capture), and the autocorrelation of the energy envelope is computed to find signal periodicity. The autocorrelation peak with highest energy within the 50–220 BPM range determines the main BPM. The confidence score measures the consistency of that peak. For music with variable tempo or complex rhythms, the manual Tap Tempo is more reliable. No data is sent to the server.
Analyze automatically or use Tap Tempo
- Upload your audio file and click Analyze BPM.
- Evaluate the result and confidence score. Use the ½ and ×2 buttons to adjust if the result seems like double or half of what's expected.
- If confidence is low, use Tap Tempo: tap the button in time with the music to measure manually.
Sources and references for this tool
These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
- Autocorrelation — Signal ProcessingWikipedia — Mathematical definition of autocorrelation — core technique in the BPM detection algorithm.
- Beat Detection AlgorithmsRice University — Overview of beat detection algorithms using energy envelope analysis.
- Web Audio API — AnalyserNodeMDN Web Docs — Web Audio analysis node — reference for spectrum and energy analysis.