Decibel Meter
Measure sound level with your microphone: live dB reading, peak, min, max and average, a 30-second chart and typical noise levels.
- No uploads
- No limits
- No signup
Your microphone stays off until you press start. Nothing is recorded or uploaded.
Readings are relative to your microphone's maximum (dBFS), so they are negative and quiet rooms read around −60. Phone and laptop mics aren't calibrated sound level meters. To see approximate dB SPL, set an offset by comparing with a real meter.
Typical noise levels
| Sound | Approx. level |
|---|---|
| Breathing | 10 dB |
| Whisper | 30 dB |
| Quiet library | 40 dB |
| Normal conversation | 60 dB |
| Vacuum cleaner | 70 dB |
| Heavy city traffic | 85 dB |
| Lawn mower | 90 dB |
| Rock concert | 110 dB |
| Ambulance siren up close | 120 dB |
Levels in red (85 dB and above) can damage hearing with long or repeated exposure.
- Input:
- Microphone
- Output:
- Sound level
- Runs on:
- Your device
- Size limit:
- None
- Account:
- Not needed
How to use Decibel Meter
Start the microphone
Press Start microphone and allow access when your browser asks. Nothing is recorded.
Watch the level
The big number and the chart show the sound level live, with the peak, minimum, maximum and average since you started.
Compare and calibrate
Check the table of typical noise levels. If you have a real sound meter, enter an offset so the readings match it.
Why Decibel Meter on Toolshed
No uploads
Everything runs in this browser tab. Your files never leave your device.
No limits
No file-size caps, no daily quotas. Process as much as your device can handle.
No signup
No account, no email, no watermark.
Frequently asked questions
How accurate is an online decibel meter?
It measures accurately relative to your microphone, but phone and laptop microphones differ in sensitivity and aren't calibrated, so it can't give exact dB SPL out of the box. Use it to compare sounds, spot changes over time or check whether one place is louder than another.
Why are the readings negative?
They are in dBFS (decibels relative to full scale): 0 dBFS is the loudest your microphone can capture, and everything quieter is negative. A silent room might read −70 dBFS and loud speech near the mic −20 dBFS.
How do I calibrate it?
Measure a steady sound with a real sound level meter (or a calibrated app) and with this page at the same spot. Enter the difference as the calibration offset; from then on the readings show approximate dB. Re-check if you change microphones.
Is my microphone audio recorded or uploaded?
No. The level is calculated live in your browser and nothing is stored or sent anywhere. The microphone turns off when you press stop or leave the page.
Are my files uploaded anywhere?
No. Decibel Meter runs entirely in your browser. Your files are processed on your device and are never sent to a server.
Is there a file size limit?
No fixed limit. The only limit is your device's memory. Very large files work best in a desktop browser.