How to use the decibel meter online
This decibel meter online turns the microphone you already have into a quick noise check. There is nothing to install, and it works on most modern phones, tablets and laptops.
- Press Allow microphone when your browser asks for access.
- Hold the device still and point the microphone toward the sound you care about, with nothing covering it.
- Watch the needle gauge for the current estimated level in dB.
- Let it run for 20 to 30 seconds, then read the minimum, maximum and average values below the gauge.
- Press Reset min / max to clear the statistics and start a fresh reading without reloading the page.
If the browser never asks for permission, check the site settings for microphone access, and close other apps that may be holding the mic, such as a video call.
How the sound level is estimated
A microphone produces a stream of tiny voltage samples. The tool reads those samples in short blocks, calculates their root mean square (a standard way to express signal strength), and converts that value to decibels on a logarithmic scale. Because decibels are logarithmic, every increase of 10 dB means roughly ten times more sound energy, and most people hear it as about twice as loud.
The key word is estimated. Consumer microphones differ in sensitivity, many devices apply noise suppression or automatic gain, and none of them were calibrated against a reference source. That is why there is a calibration offset slider: it adds or subtracts a fixed amount from every reading so you can line the tool up with a trusted meter. All processing runs locally in your browser; the audio is never sent anywhere.
Typical sound levels and practical tips
| Sound | Approximate level |
|---|---|
| Whisper nearby | ~30 dB |
| Quiet library or bedroom at night | ~35–40 dB |
| Normal conversation | ~60 dB |
| Busy restaurant | ~70–75 dB |
| City traffic from the sidewalk | ~80 dB |
| Lawn mower, blender | ~85–90 dB |
| Motorcycle passing, power tools | ~95–100 dB |
| Rock concert near the speakers | ~105–110 dB |
As general guidance, health bodies such as NIOSH and the WHO note that listening to sound around 85 dB for hours at a time can damage hearing over the long run, and each extra 3 dB roughly halves the time that is considered safe. Treat the table and these numbers as rules of thumb rather than medical advice.
A few ways to get more useful readings:
- Compare, don’t certify. Measure two rooms with the same device and the same position; the difference between them is more trustworthy than either absolute number.
- Keep the distance fixed. Moving from one meter to half a meter from a source can add several decibels on its own.
- Use the average for reports. If you are documenting a noisy neighbor or a loud office, note the time, the average and the peak.
- Get a proper meter for official needs. Workplace compliance or legal disputes call for a calibrated Class 1 or Class 2 sound level meter.