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Online decibel meter

Tap “Start measuring” and allow the microphone – you instantly see how loud it is. Important: phone and laptop microphones are not calibrated, so the dB(A) figure is only a rough guide.

Uncalibrated: Browser microphones do not measure true decibels. The dB(A) reading is an estimate that can be off by many decibels – not suitable for workplace safety, noise complaints or expert reports.

Ready. After you start, the browser asks for the microphone.

≈–dB(A)

rough estimate, uncalibrated

Measured level: –

Minimum
–
Equivalent level Leq
–
Maximum
–
Duration
0:00
Calibrate with a sound level meter

Hold a sound level meter next to your device, play a steady sound and enter its reading.

For comparison (figures from sources)

  • 70 dB(A) recovery: rest periods should stay below this (German Environment Agency)
  • 80 dB(A) lower exposure action value at work (German regulation, daily average) (§ 6 LärmVibrationsArbSchV)
  • 85 dB(A) upper exposure action value at work (German regulation, daily average) (§ 6 LärmVibrationsArbSchV)
  • 90–110 dB(A) measured in discos and at live music events (German Environment Agency)
  • 110 dB(A) reachable with earphones on music players (German Environment Agency)

The microphone signal is analysed only in your browser and is neither stored nor sent.

dB
Estimate = measured level in dBFS(A) + this offset. The default of 100 dB is an assumption. Set it properly with a real sound level meter via “Calibrate”.
Your inputs are saved in this browser only.

Result

How it is calculated

How loud is it in the office, the nursery or by the road? This tool shows it live – with one honest caveat: without a calibrated microphone, no phone or laptop can measure true decibels.

How it works

  1. Tap “Start measuring” and allow microphone access.
  2. Keep the device still and do not cover the microphone. The big number is the estimated level; below it is the measured value in dBFS.
  3. Minimum, maximum and the equivalent level (Leq) keep running until you stop or reset.
  4. If you own a real sound level meter, “Calibrate” sets the offset for this device.

How it is calculated

The microphone is opened without automatic gain, noise suppression or echo cancellation. Every 100 ms the spectrum is A-weighted according to IEC 61672-1 and the level is calculated relative to digital full scale (dBFS). The display uses “Fast” time weighting (125 ms); Leq is the energy average over the whole measurement. The dB(A) estimate adds a fixed offset – without calibration, that is just an assumption.

Honest limits

Microphones, cases and browsers differ a lot, and some devices still adjust the gain. According to NIOSH, even its own lab-tested app reaches ±2 dB(A) only on iPhones; Android devices could not be verified because of the many manufacturers. In a browser the uncertainty is larger. Very quiet rooms often fall below the microphone’s self-noise, very loud ones overload it. Workplace or legal measurements need a certified Class 1 or 2 meter.

Frequently asked questions

Can my phone measure decibels?

Only roughly. Without calibration the reading is a guide that can be off by many decibels. It is still useful for before/after comparisons on the same device.

What does dBFS mean?

Decibels relative to digital full scale: 0 dBFS is the loudest signal the microphone can deliver, everything below is negative. It only relates to real sound pressure after calibration.

What is the equivalent level Leq?

The steady level that would carry the same sound energy over the measurement as the fluctuating noise did. Loud peaks weigh more than quiet phases.

How many decibels are dangerous?

German workplace rules (§ 6 LärmVibrationsArbSchV) use action values of 80 and 85 dB(A) as daily averages, and the German Environment Agency recommends rest periods below 70 dB(A). This tool cannot check that reliably.

Is anything recorded?

No. The signal is analysed live and is neither stored nor sent.

Sources and legal basis

As of:

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