HowLoudClassroom noise meter
Press Start
A noise level monitor the whole class can see
Put this page on the projector or an interactive whiteboard, set a limit, and press Start. The disc stays green while the room is calm, turns orange as the level approaches the limit, and flashes red with a soft chime when the class is too loud. The counter shows how many times the limit was crossed, which makes a simple, fair goal for the lesson: "let's keep it under three today".
The meter uses the same microphone engine as the online decibel meter, so the limit is a real dB(A) value rather than an arbitrary scale. It runs in the browser on any Chromebook, laptop, iPad or Android tablet with a microphone. Nothing is recorded.
Which limit should I set?
| Activity | Suggested limit | Why |
|---|---|---|
| Silent reading, tests | 50–55 dB | Just above the room's background noise; whispering stays under it |
| Independent work, quiet talking | 60–65 dB | Normal one-to-one conversation is about 60 dB at arm's length |
| Group work, discussions | 70 dB | Several groups talking at once; above this, voices escalate |
| Practical lessons, indoor play | 75–80 dB | Loud but still safe for hearing; keeps shouting in check |
Classroom background noise with nobody talking is usually 40–50 dB (ventilation, corridor, traffic). If the disc turns orange before anyone speaks, raise the limit by 5 dB or move the laptop away from the projector fan.
Tips for teachers
- Full screen hides the browser chrome so the disc fills the board. Press Esc to leave.
- Turn the chime off for younger pupils who find it startling; the red flash and the wobble are enough.
- Use the counter as a class score. Reset it by pressing Stop and Start again.
- Position matters. A laptop at the front reads the front rows loudest. For a fairer reading put the device in the middle of the room or use a phone with the HowLoud app as the microphone.
- Explain the number. Older students like knowing that 60 dB is a conversation and 85 dB is where hearing damage starts; the decibel chart is a good five-minute lesson.
Frequently asked questions
Is the classroom noise meter free?
Yes, completely: no account, no download and no ads. It works in any current browser with a microphone.
Does it record the children?
No. The browser passes the microphone signal to the page, the page computes a level several times a second, and the audio is discarded at once. Nothing is stored or sent anywhere.
Why does the disc turn red when nobody is talking?
Fans, projectors and heating can push a room to 50–55 dB. Check the reading with the class silent and set the limit at least 10 dB above it.
Can I use it for a library, office or open-plan space?
Yes. Set a limit that matches the space (about 55 dB for a library, 65 dB for an office) and leave the page open on a spare screen.