How to measure noise
- Click Start measuring and allow the microphone.
- Put the computer or phone where you want to measure, with the microphone uncovered.
- Read the live level, and the Min, Average and Max since you started. Reset starts a new measurement.
- If you have a reference (another meter, or a sound of known level), move Calibration until the reading matches.
How loud is loud?
| Level | Sounds like |
|---|---|
| 30 dB | Whisper, quiet library |
| 40 dB | Quiet room at night |
| 60 dB | Normal conversation |
| 70 dB | Busy office, vacuum cleaner |
| 85 dB | Heavy traffic. Hours of it can harm hearing |
| 100 dB | Motorbike, loud concert |
Every 10 dB sounds about twice as loud. Long exposure above 85 dB can damage hearing.
How the meter works
The page reads your microphone with the browser’s noise suppression and automatic volume turned off, so they can’t flatten the level. It averages the sound power the way sound level meters do (“fast”, 125 ms) and shows it on a decibel scale. Nothing is recorded.
For classrooms
Teachers: the classroom noise meter adds a “too loud” limit, colours the number green, amber or red, and fills the screen for a projector.
