---
title: "Classroom Noise Meter: Calm, OK, Too Loud | Sprout Assembly"
description: "A free classroom noise meter for the board: your device's microphone drives a calm, OK or too-loud light. Sound is analysed on the device, never recorded."
url: https://sproutassembly.sbs/classroom-noise-meter/
---

# Classroom noise meter

Put the meter on the board and let the class see their own volume: a light for calm, OK and too loud, a quiet-streak timer, and thresholds you set for the activity.

## Setting it up for your room

1. Press **Start listening** and allow the microphone. Put the device where it hears the whole room, not right next to one table.
2. Watch the level while the class works the way you want, then drag *Calm up to* just above it. Set *Too loud from* where talk stops being useful. The marks on the bar show both.
3. If the bar barely moves, raise *Microphone sensitivity*; if it sits near the top, lower it.
4. Press the full-screen button so the lights fill the board. *Quiet streak* counts how long the room has stayed out of the red, which makes a good class challenge.

## What the numbers mean

The level runs from 0 to 100 and is relative to your microphone: it is not a reading in decibels, and the same room will read differently on a laptop, a tablet or a phone. The page asks the browser for the raw signal, measures its average strength several times a second and smooths it so the bar rises quickly and settles slowly. *Change the light after* makes the light wait before switching, so one dropped book or a burst of laughter does not turn it red.

Your settings are remembered in this browser. The sound itself is never stored: as soon as a level is measured, the audio is gone.

## Questions

**Why does the page say the microphone is blocked?**

Your browser or device has been told not to let this site use the microphone. Click the microphone or lock icon in the address bar, allow it, then press start again. On a school device an administrator may have turned it off.

**Does it record the class?**

No. The audio is analysed in this browser to work out a loudness number, then discarded. Nothing is recorded or sent anywhere, and the microphone is released when you press Stop or close the page.

**Can I use it as a decibel meter?**

No. Phone and laptop microphones are not calibrated, so the 0 to 100 level only compares louder with quieter in the same place on the same device.