Measure noise in decibels with your microphone: live dB(A), average, max, safe listening time and a classroom noise light
How to use
Press Start measuring and allow the microphone. Voice processing is switched off so the level is not adjusted for you.
Watch the live level in decibels, with the minimum, maximum and average since you started.
Choose A weighting for everyday noise or C for loud music, and Fast or Slow response.
For better accuracy, put a real sound meter next to your device, type what it shows and press Match it.
For a class or an office, open the classroom noise light, set a limit, and put it on a big screen.
Why use this tool
Real A and C weighting: Levels are weighted the way the IEC 61672 standard for sound level meters describes, so a low hum counts less than a voice, just as your ears hear it.
Average noise, done properly: The average is an Leq, the energy average used in noise regulations. Half a minute at 90 dB and half at 60 dB averages 87 dB, not 75.
Safe listening time: See how long the average level can be heard each day by the NIOSH recommendation of 85 dB(A) for 8 hours, halved for every 3 dB more.
Classroom noise light: A full screen green, yellow and red face that reacts to the room, with a limit you set, a count of how often it got too loud, and the screen kept awake.
Calibration that is remembered: Match a reference meter once and the offset is saved in your browser for next time.
Last minute graph: A live history of the level so you can see peaks and quiet moments at a glance.
Frequently asked questions
How accurate is an online decibel meter?
It depends on the microphone. Phones and laptops are not certified meters, so an uncalibrated reading can be off by several decibels. Calibrating against a real meter in steady noise brings it much closer for everyday levels. Very loud sound above about 100 dB can exceed what small microphones capture.
What is dB(A)?
Decibels with A weighting, which reduces very low and very high frequencies the way human hearing does. It is the unit used for workplace noise limits, neighbour noise complaints and hearing safety.
How loud is too loud?
Normal conversation is around 60 dB. Long exposure above 85 dB(A) can damage hearing: 8 hours a day at 85 dB, 1 hour at 94 dB and only 15 minutes at 100 dB by the NIOSH recommendation.
Why does the meter read 0 or very low?
Check that the right microphone is allowed in your browser and not muted. Some devices apply their own noise cancellation that cannot be switched off by a website, which lowers the reading.
Is any sound recorded or uploaded?
No. The microphone signal is analysed in your browser as it arrives and nothing is saved or sent anywhere.