Live BPM / Tempo Detector - Microphone or Tap Tempo

How to use this tool

1. Choose Listen to use the microphone, or Tap to measure a beat without microphone access.
2. In Listen mode, click Start Listening and allow microphone access. Play music near the selected microphone.
3. In Tap mode, tap the large pad on each beat, or use Space or Enter. The tempo uses up to the last eight intervals and resets after about three seconds idle.
4. Use ÷2 or ×2 if the beat is being counted at half-time or double-time. Click Stop to end microphone listening.

How BPM detection works

In Listen mode, the tool analyses microphone input in real time with the Web Audio API AnalyserNode. It computes the root-mean-square (RMS) energy of successive audio windows and detects sudden energy increases, or onsets. The median time between recent onsets is converted to beats per minute. A level meter shows whether audio is reaching the detector, and the tempo card briefly flashes when an onset is accepted. The microphone graph is used only for analysis and is not connected to speakers.

Choose Listen for automatic detection or Tap for a manual reading. In Tap mode, tap the large pad once on each beat, or press Space or Enter when focus is outside a control. Tap mode does not ask for microphone permission. It averages up to the last eight tap intervals and starts a fresh count after about three seconds without a tap. The first tap starts a count; the next tap supplies the first interval.

Common tempo markings

• Largo - very slow (< 60 BPM)
• Adagio - slow (66–76 BPM)
• Andante / Moderato - walking pace (76–108 BPM)
• Allegro - fast (120–168 BPM)
• Presto - very fast (> 168 BPM)

Privacy

Microphone audio is analysed entirely in your browser. No audio data is recorded or transmitted anywhere.

Manual tap tempo

Automatic beat detection works best for recordings with clear, consistent percussion. For live performances, ambient recordings, or music with irregular rhythm, select the in-page Tap mode and tap once on each beat. Its rolling average helps smooth small timing differences while you tap; a long pause clears the previous count. The dedicated full Tap Tempo tool also includes beat subdivisions for more detailed practice.

Genre BPM ranges

Time signatures and doubled/halved tempo

BPM counts beats, but beats are defined by the time signature. In 4/4 (the most common time signature), there are four quarter-note beats per measure. In 3/4 (waltz time), there are three. If a song is detected at 130 BPM, it could also be perceived as 65 BPM by counting only every other beat (half-time feel), or 260 BPM by subdividing into eighth notes (double-time feel). This is why the same track can be described at different BPMs in different DJ or fitness contexts.

The ÷2 and ×2 controls apply that half-time or double-time interpretation to the displayed reading, whether it came from listening or tapping. The original detected or tapped tempo remains labeled below the number, and tempo readings are limited to 20–300 BPM. These controls change the display only; the onset and tap histories continue to represent the original measurement. For example, a 130 BPM reading can be shown as 65 BPM or 260 BPM without changing the underlying intervals.