How to use the Classroom Noise Meter
- Start listening. Press Space or click Start listening, then allow the microphone when the browser asks. Nothing is recorded.
- Set the limit. Drag the noise limit in Settings, or press + and −. If the meter is always red or never moves, click Calibrate now during a quiet moment.
- Pick a display. Press 1–4 for a gauge, a bar, rising bubbles or a face that gets more and more surprised.
- Watch the streak. The quiet streak counts how long the class has stayed under the limit. Press R to reset the counts for a new lesson.
Classroom ideas
- Beat the record: show the best quiet streak at the start of independent work and challenge the class to beat it.
- Bubbles for little ones: younger pupils understand calm bubbles drifting up far faster than numbers — the bubbles grow and race when the room gets loud.
- Agree the limit together: raise the limit for group work and lower it for reading, and talk about why each activity needs a different level.
- Pair it with voice levels: put the meter on the Classroom Board next to Voice Levels so pupils see the target and the reality side by side.
- Reward, don’t punish: count the “too loud” moments over a week and celebrate the quietest lesson rather than calling out the loudest.
Keyboard shortcuts
| 1 – 4 | Gauge, bar, bubbles or face display |
| + | Raise the noise limit |
| − | Lower the noise limit |
| F | Present full screen |
Frequently asked questions
Is the sound recorded?
No. The browser measures the loudness of the sound many times a second on your own computer and throws it away. Nothing is saved, recorded or sent over the internet.
Why does the browser ask for the microphone?
Web pages cannot hear anything without your permission. Click Allow once; most browsers remember the choice for this site. You can take it back any time from the icon in the address bar.
Is it measuring real decibels?
It shows a relative level from 0 to 100, not calibrated decibels: every microphone is different. Use Calibrate now in a quiet moment so that calm reads low and set the limit by watching a normal working buzz.
The meter barely moves. What can I do?
Raise the sensitivity in Settings, check that the right microphone is selected in your computer’s sound settings, and keep the laptop away from the fan or projector noise.
Will it keep listening in another tab?
It pauses while the tab is hidden and carries on when you come back, so it never runs in the background without you seeing it.
Updated October 31, 2026 · Free to use in any classroom, no account needed.