How to use the classroom noise meter
- Press Start and allow microphone access when your browser asks.
- Choose a display: the monster sleeps while the room is calm, opens its eyes as noise rises and wakes up (and shakes) when it's too loud. The face and bar views work the same way with green, yellow and red.
- Set the limit during a normal working moment: watch the level for a minute, then move the limit slightly above it.
- Press Full screen to show only the display on your projector or smart board.
- Optional: turn on the gentle chime, which plays when the class stays above the limit for more than a second and a half (at most once every few seconds).
Ideas that work in class
- Earn quiet minutes. The "quiet time earned" counter adds up every second the room stays under the limit. Set a goal, for example 10 quiet minutes for five minutes of free time.
- Don't wake the monster. Younger classes love keeping the monster asleep during independent work.
- Different limits for different activities. Lower for silent reading, higher for group work. Your last settings are remembered on the device.
- Let students set it. Ask the class what "partner voice" looks like on the meter and set the limit together.
Privacy: nothing is recorded
The classroom noise meter only measures how loud the room is. The microphone signal is processed inside your browser, moment by moment, and is never recorded, saved or sent anywhere. Press Stop or close the tab and the microphone switches off. Your browser shows a microphone icon while it's in use.
Getting reliable readings
- Placement matters. A laptop at the front of the room hears the front rows more. Place the device centrally if you can.
- Use the sensitivity slider if the meter reads high even when the class is quiet (lower it) or barely moves (raise it).
- Avoid fans and speakers right next to the microphone; constant noise raises the baseline.
- It's a relative level, not decibels. Classroom laptops and tablets don't have calibrated microphones, so the meter shows 0–100. It's consistent on the same device, which is what you need for a limit.
How we tested this tool
We tested the classroom noise meter in Google Chrome on Windows by feeding it a generated test signal in place of a microphone and checking that the level rises with volume, the display switches from calm to near to loud at the limit, quiet time only counts while under the limit, and the "too loud" counter increases once per loud moment. We haven't tested it in a real classroom yet. Teachers: tell us how it works for your class and we'll add your feedback here.
Frequently asked questions
Does the classroom noise meter record my students?
No. The microphone signal is analyzed in your browser to measure loudness only. Nothing is recorded, stored or sent anywhere, and the microphone turns off when you press Stop or close the page.
Does it show decibels?
It shows a 0–100 noise level rather than decibels, because laptop and tablet microphones aren't calibrated. The level is consistent on the same device, which is what matters for keeping a class below the limit you set.
What limit should I set?
Start the meter during a normal working moment, note the level, and set the limit a little above it. Use the sensitivity slider if your microphone reads too high or too low. Your settings are remembered on that device.
Can I show it on a projector or smart board?
Yes. Press Full screen to hide everything except the monster, face or bar and the status text. The computer connected to the board needs a working microphone.
Is it free?
Yes, it's free with no account or download.