How to use the decibel meter
- Press Start and allow microphone access when your browser asks.
- Hold the device still, microphone pointing toward the sound, and avoid covering it with your fingers or a case.
- Read the live value and watch the graph. The average is an energy average (Leq), the standard way to summarize noise over time, so short loud bursts count properly.
- Check the safe time under the reading if it climbs above 85 dB.
- Press Reset to start a new measurement, for example in a different room.
How loud is it? Common sound levels
| dB(A) | Typical sound |
|---|---|
| 30 | Whisper, quiet bedroom at night |
| 40 | Library, quiet living room |
| 60 | Normal conversation, about 1 m away |
| 70 | Vacuum cleaner, busy street |
| 85 | Heavy traffic, food blender – hearing risk with long exposure |
| 100 | Motorcycle, power tools, loud concert |
| 120 | Siren up close – threshold of pain |
Decibels are logarithmic: every 10 dB sounds roughly twice as loud, and every 3 dB is twice the sound energy. That's why 90 dB is far more harmful than 85 dB even though the numbers look close.
Safe listening time
The meter uses the NIOSH recommendation: 85 dB(A) for up to 8 hours a day, halving the safe time for every 3 dB above that. So roughly 4 hours at 88 dB, 1 hour at 94 dB and 15 minutes at 100 dB. If a place regularly measures above 85 dB, hearing protection is a good idea.
How accurate is a decibel meter online?
A decibel meter online uses your device's microphone, so the result is an estimate. We switch off the browser's automatic gain control, echo cancellation and noise suppression so the microphone isn't constantly adjusting itself, which makes readings far steadier. Even so, every phone and laptop microphone is slightly different, and very loud sounds can exceed what a small microphone can capture.
Calibrate it for better results: place your device next to a real sound level meter (or a calibrated meter app) in front of a steady sound, then move the calibration slider until both show the same value. Your calibration is remembered on this device.
For workplace safety reports, legal disputes or building regulations, use a certified Class 1 or Class 2 sound level meter.
iPhone decibel meter and Android
This page works as an iPhone decibel meter in Safari or Chrome, with no app to install: tap Start and allow the microphone. The bottom microphone is the main one, so point the bottom edge of the iPhone toward the sound. If you own an Apple Watch, its Noise app is another option; the iPhone's built-in Hearing control shows headphone volume, not room noise. On Android, the sound meter online works in Chrome, Samsung Internet and Firefox the same way.
Sound meter online vs noise meter app
A sound meter online and a noise meter app measure the same thing with the same microphone. A browser tool needs no installation and no account, and because everything runs on your device, nothing is uploaded. Apps can add background logging. For quick checks of a room, a gym, a classroom or a workplace, the online version is usually all you need. Teachers who want a classroom display can use our classroom noise meter.
How we tested this tool
We tested the decibel meter in a browser by feeding it a generated tone instead of a real microphone and checking that every 10× increase in signal amplitude raised the reading by 20 dB, that min, average and max update correctly, and that the safe-time message changes at 85 dB. We haven't compared it with a certified meter on real devices yet. If you have a reference meter, tell us your results.
Frequently asked questions
How accurate is an online decibel meter?
It gives a useful estimate, typically within a few decibels once calibrated, but it is not a certified sound level meter. Phone and laptop microphones vary, and very loud sounds can exceed what the microphone can capture. For legal or workplace measurements, use a Class 1 or Class 2 meter.
Is there an iPhone decibel meter without an app?
Yes. Open this page in Safari, tap Start and allow the microphone. If you have an Apple Watch, its Noise app also measures environmental sound; the iPhone's built-in Hearing control shows headphone levels rather than room noise.
How loud is too loud?
NIOSH recommends limiting exposure to 85 dBA over an 8-hour day and halving the time for every 3 dB above that: about 4 hours at 88 dB, 2 hours at 91 dB and 15 minutes at 100 dB.
What is the difference between dB and dB(A)?
dB(A) is weighted to match human hearing, which is less sensitive to very low and very high frequencies. Most noise rules use dB(A). This meter applies standard A-weighting (IEC 61672 curve) when the option is on.
Does the noise meter record audio?
No. The microphone signal is analyzed in your browser to calculate loudness only. Nothing is recorded, saved or uploaded, and the microphone switches off when you press Stop.