Classroom Noise Monitor for Teachers

Set a noise limit, put the live meter on your projector, and give students a visible target they can manage themselves. An alarm sounds after sustained noise above the limit, and each breach is logged for the session.

Your microphone is used only to measure loudness in this browser tab. No audio is recorded, saved, or sent anywhere.

Limit

0 Level (0–100)

00:00 Session

0 Breaches

Press Esc to leave projector mode.

Level is a relative 0–100 loudness reading for this room and this device — it is not a calibrated decibel (dB) measurement and should not be used for hearing-safety decisions. Calibrate once at the start of a lesson so the meter matches your room.

Settings

Noise limit 40 The alarm sounds when the class stays above this level for about a second, so a single chair scrape is ignored. Microphone sensitivity Raise this in a large or quiet room; lower it if the meter is always high. Alarm volume 100% Applies to the alarm tone only.

Alarm sound Screen flash

Alarm Log

Each time the class goes over the limit, the time and how long it lasted are recorded here.

No breaches yet. Start monitoring to build a log.

Classroom Tips

Run Calibrate Quiet Room once while the class is settled. Every laptop microphone is different, and calibrating makes the meter match your room instead of a generic guess.
Start the limit around 40 for independent work and 60–70 for group work, then adjust after watching it for a few minutes.
Use Projector Mode so students can see the bar before the room gets too loud and correct the volume without another verbal reminder.
Treat the breach count as class-level feedback, not as a way to identify individual students. The tool measures overall room loudness only.
Keep this tab in front while monitoring. Browsers can pause background tabs, which stops the meter.

How to use the classroom noise monitor

Start Monitoring and allow microphone access when your browser asks.
Settle the room for a moment and select Calibrate Quiet Room. Then choose a noise limit that matches the activity.
Turn on Projector Mode so students can see the live bar. Adjust the limit or microphone sensitivity if normal classroom sound is consistently too high or too low.

The number on this tool is intentionally a relative classroom level, not a decibel reading. Different laptops, microphones, room sizes, and browser audio settings respond differently, so calibration and a quick real-room adjustment are more useful than treating one number as a universal standard.

Match the noise limit to the activity

Quiet independent work and collaborative group work should not use the same target. On this 0–100 meter, a limit near 40 can be a practical starting point for quiet work, while 60–70 gives groups more room to talk. Watch the bar for a few minutes and move the limit until it reflects the sound level you actually want students to maintain.

During reader's theater rehearsal, the monitor can help several groups practice expressive reading in the same room without one group gradually overpowering the others. Set a higher collaborative limit, project the meter, and use the session log to reset expectations between rehearsal rounds rather than interrupting every rise in volume.

Looking for material to rehearse? Browse the free reader's theater resources or the full script collection.

If the meter is not responding as expected

Check that this site has microphone permission in your browser.
Keep the monitoring tab visible instead of leaving it in the background.
Run Calibrate Quiet Room again after changing computers, rooms, or microphones.
Raise microphone sensitivity if the meter barely moves; lower it if ordinary room sound immediately fills the bar.

For more quick classroom prep, try the Word Search Generator, Crossword Generator, or Cloze Generator.