How to use
- Press Start and allow microphone access.
- Watch the current level, the gauge and the peak marker.
- Read the session max and average, then press Stop.
Want to know how loud a room, a fan, a neighbour’s music or your own recording setup is? This online decibel meter reads your microphone and shows the sound level live, along with the peak, the highest level of the session and the session average. It is handy for comparing two sounds on the same device, checking whether a space got quieter after a change, or watching input levels before you record.
Every 0.1 seconds the tool takes 2,048 samples through the Web Audio API and computes the RMS level as 20 × log10(RMS), which is the current level. The peak uses the largest sample value. Levels are clamped at -160 dB, and the gauge maps -60 dB to 0 dB on a square-root curve so quiet sounds stay visible. The session max and average are taken from the current-level readings and reset each time you press Start; the average is the arithmetic mean of the dB values. Browser echo cancellation, noise suppression and automatic gain are switched off so they do not change the reading.
All values are dBFS, where 0 is the loudest signal the input can carry. Phone and laptop microphones are not calibrated, so the numbers cannot be converted to dB SPL and are not a legal or occupational noise measurement. Sound is analysed in the browser and is never recorded, uploaded or saved.