BPM Detector - Tap Tempo
Detect song BPM via microphone with real-time analysis. Includes tap-tempo fallback, beat history graph, and one-click copy.
Runs in your browser. No data leaves your device.
Frequently Asked Questions
How does the BPM Detector work?
The microphone signal is routed through a Web Audio API BiquadFilter lowpass at 200 Hz to isolate the bass. An AnalyserNode reads time-domain data each frame, and the tool detects onsets by tracking energy spikes above a moving threshold. It builds an inter-onset interval histogram with Gaussian smoothing and a tempo prior to find the most likely BPM.
Can I set the BPM manually?
Yes. You can tap the beat with the Tap button or spacebar (4+ taps needed), type a BPM value directly, or let auto-detection find it. Lock the BPM to freeze detection.
Is my audio recorded or sent anywhere?
No. All processing happens entirely in your browser using the Web Audio API. No audio data is recorded, stored, or transmitted. The microphone stream is discarded when you stop listening.