Classroom Noise Meter

✨ Features

  • Three displays: a needle meter, bouncing balls that jump higher the louder it gets (great for kids), and a green-yellow-red traffic light. Each level has its own color, label and face
  • Set your own Quiet and Too loud lines, and tune the microphone sensitivity in 3 seconds with “Set current sound as baseline”
  • When it gets too loud, a big “Quiet, please!” fills the screen, with an optional alert sound (on/off, adjustable volume)
  • A quiet timer counts how long the room stays below Too loud and celebrates when you reach your goal. Your best run is shown too
  • Fullscreen and a Zen mode that hides the buttons. The screen stays on while it's listening (in supported browsers)
  • Nothing is recorded or uploaded. Microphone sound is only turned into a loudness number on your device; only your settings are saved

🪄 Great for

Classrooms

During group work or independent study, students can see their own volume and adjust it — fewer reminders from you.

Young kids

With the bouncing balls, keeping the room calm becomes a game: “Let's keep the balls still!”

Study halls and libraries

Keep the current noise level on a big screen in places that need to stay quiet, and set quiet time goals.

Meetings and events

Check how noisy the room is, or make “wait until it's quiet” visible before you begin.

🔒 Privacy

Microphone sound is only turned into a loudness number inside your browser. It is never recorded or sent to a server. Only your settings (display, limits and so on) are saved in this browser's localStorage. Press Stop or close the page and the microphone is released.

❓ FAQ

Is the audio recorded or sent anywhere?

No. Microphone sound is processed inside your browser (Web Audio) and turned into a loudness number. Nothing is recorded, stored or sent to a server. Only your settings, like the display and limits, are saved. Press Stop or close the page and the microphone is released, and your browser's microphone indicator goes away.

Can I use it as an accurate decibel meter?

No. The same sound comes in at very different levels depending on the device, microphone and browser, so it doesn't show decibels. The display is a relative 0–100 scale for seeing whether the room is getting louder or quieter. To measure or record noise levels, use a proper sound level meter.

The needle maxes out right away / barely moves

The microphone sensitivity needs adjusting. While the room is quiet, press “Set current sound as baseline”: it listens for 3 seconds and sets the sensitivity so that sound lands in the middle of Quiet. To adjust by hand, move “Microphone sensitivity” in Settings. To change what counts as too loud, move the “Start of Too loud” line.

Can it play a sound when the class gets too loud?

Yes. Turn on “Play sounds” in Settings and an alert plays when the level reaches the Too loud line (at most once every 4 seconds, with adjustable volume). A short chime also plays when you reach your quiet time goal. Sound is off by default — the on-screen “Quiet, please!” works on its own. While a sound plays, listening pauses for a moment so the meter doesn't pick it up.

The microphone doesn't work

If you blocked the microphone, click the lock (or microphone) icon in the address bar, allow the microphone for this site, and press Start again. On iPhone and iPad you can also change it in Settings → Safari → Microphone. It may fail to open if another app, such as a video call, is using the microphone. Microphones only work on https pages, so open it from https://tools.omikuji.dev/.

How is “quiet time” measured?

It's how long the level has stayed below the Too loud line. If the level stays at or above the line for about 0.4 seconds, it goes back to zero and starts again (a single cough or bump won't reset it), and your longest run is shown as “Best” (it resets when you close the page). Set a goal (30 seconds to 15 minutes) in Settings and you'll get a “Goal reached!” celebration when you hit it.

🔗 Related tools

Countdown Timer Pomodoro Timer Stopwatch Sand Timer Random Name Picker Random Number Generator Team & Seat Maker Online Scoreboard Seating Chart Maker Metronome
Quiet 0/100

When your browser asks to use the microphone, choose Allow.

Nothing is recorded or uploaded. Sound is only turned into a loudness number on this device.

Quiet time 0:00 Goal 1:00 Best 0:00

Nothing is recorded or uploaded. Sound is only turned into a loudness number on this device. Not a calibrated sound level meter. The number is a relative 0–100 scale, not decibels.

Classroom Noise Meter

A free classroom noise meter that listens through your microphone and shows how loud the room is on a big screen — Quiet, OK or Too loud, with colors and faces. Choose a needle meter, bouncing balls or a traffic light, and set your own limits. When the class gets too loud it shows a warning (with an optional alert sound), and it times how long everyone stays quiet and celebrates when you hit your goal. Nothing is recorded or uploaded: the sound is turned into a loudness number right on your device.

How to use it

  1. Press “Start listening” and allow the microphone when your browser asks
  2. While the class is quiet, press “Set current sound as baseline” to tune the sensitivity automatically
  3. Pick the meter, bouncing balls or traffic light, go fullscreen and put it on the projector or TV
  4. If it reacts too much or too little, move the Quiet and Too loud lines or the sensitivity in Settings

Not a calibrated sound level meter

The same sound comes in at very different levels depending on the microphone and browser of each laptop, tablet or phone. So this tool doesn't show decibels (dB). It uses a relative 0–100 scale to show whether the room is louder or quieter than before. If you need to measure or record noise levels, use a proper sound level meter.

Features

  • Three displays: a needle meter, bouncing balls that jump higher the louder it gets (great for kids), and a green-yellow-red traffic light. Each level has its own color, label and face
  • Set your own Quiet and Too loud lines, and tune the microphone sensitivity in 3 seconds with “Set current sound as baseline”
  • When it gets too loud, a big “Quiet, please!” fills the screen, with an optional alert sound (on/off, adjustable volume)
  • A quiet timer counts how long the room stays below Too loud and celebrates when you reach your goal. Your best run is shown too
  • Fullscreen and a Zen mode that hides the buttons. The screen stays on while it's listening (in supported browsers)
  • Nothing is recorded or uploaded. Microphone sound is only turned into a loudness number on your device; only your settings are saved

Keyboard shortcuts

  • Space to start / stop listening
  • 1, 2, 3 to switch between meter, balls and traffic light
  • C to set the current sound as baseline
  • F for fullscreen, Esc to close settings or Zen mode

Great for

Classrooms

During group work or independent study, students can see their own volume and adjust it — fewer reminders from you.

Young kids

With the bouncing balls, keeping the room calm becomes a game: “Let's keep the balls still!”

Study halls and libraries

Keep the current noise level on a big screen in places that need to stay quiet, and set quiet time goals.

Meetings and events

Check how noisy the room is, or make “wait until it's quiet” visible before you begin.

Related tools

⏳ Countdown Timer🍅 Pomodoro Timer⏱️ Stopwatch⌛ Sand Timer🙋 Random Name Picker🔢 Random Number Generator👥 Team & Seat Maker🏆 Online Scoreboard🪑 Seating Chart Maker🎵 Metronome

Privacy

Microphone sound is only turned into a loudness number inside your browser. It is never recorded or sent to a server. Only your settings (display, limits and so on) are saved in this browser's localStorage. Press Stop or close the page and the microphone is released.