Noise Level Meter - Decibel Meter Online
Measure ambient sound levels in real time using your microphone. Displays approximate decibel readings with a visual level indicator.
Runs in your browser. No data leaves your device.
Frequently Asked Questions
How does the Noise Level Meter work?
The tool captures microphone input via getUserMedia and routes it into a Web Audio API AnalyserNode. It reads time-domain sample data every animation frame, computes the root-mean-square (RMS) amplitude, and converts that to an approximate decibel value using 20 * log10(rms). The result is an uncalibrated relative dB level displayed in real time.
How accurate is the decibel reading?
The readings are approximate and relative, not calibrated. Consumer microphones are not precision instruments, so values may differ from a professional sound level meter. The tool is useful for comparing relative noise levels.
Does it record my audio?
No. The microphone input is analyzed in real time to compute volume levels and immediately discarded. No audio is recorded, stored, or transmitted anywhere.
Why do I need to grant microphone permission?
The browser requires explicit permission to access your microphone for privacy. The tool only reads volume levels from the microphone signal -- it does not listen to speech or record anything.