Online Decibel Meter

Create a Device-Specific Estimate

Compare relative dBFS with a calibrated physical sound level meter to save a single device-specific offset. The result remains an unweighted, non-certified estimate.

Why Calibrate Your Meter?

Consumer microphones and browser audio processing vary. Calibration stores one offset derived from one comparison point.

  • •
    Microphone Differences: Phone and laptop microphones vary in sensitivity, frequency response, automatic processing, and clipping behavior.
  • •
    Single-Point Offset: The tool subtracts its dBFS reading from one physical-meter reading and stores the resulting offset.
  • •
    What It Cannot Correct: One offset cannot correct frequency response, automatic gain, compression, clipping, microphone directionality, or changes in browser and device processing.

Understanding the Limits

Calibration changes the displayed scale; it does not certify the browser or microphone as a sound level meter.

  • ⚠Consumer microphones have physical limitations
  • ⚠A single offset may not transfer across frequencies, input levels, devices, or browsers
  • ⚠Noise reduction, automatic gain, compression, and clipping can change the result
  • ⚠For critical work, use certified equipment

What You'll Need

Reference Meter

A calibrated physical sound level meter with suitable range and documented calibration. A phone app is not a traceable reference for this process.

Steady Sound Source

A steady source that both devices can observe without obvious noise-floor or clipping behavior. Avoid rapidly changing sounds.

Calibration Steps

1

Start Measurement

Click 'Start Measurement' on the main page and wait until the relative dBFS display is reasonably stable.

2

Measure with Reference

Place your reference decibel meter next to your device. Both should measure the same sound source at the same distance.

3

Click Calibrate Button

While both meters are measuring, click the 'Calibrate' button in our tool.

4

Enter Reference Value

Enter the decibel reading from your reference meter in the calibration dialog.

5

Save Calibration

Click 'Calibrate' to save the single-point offset in this browser. Future readings will be labeled as device-specific estimates.

Tips for Best Results

  • ✓Use a steady source that is within the usable range of both devices and does not visibly clip
  • ✓Make sure both meters are at the same distance from the sound source
  • ✓Wait for readings to stabilize before calibrating
  • ✓Keep device position, orientation, browser, and audio settings unchanged during comparison
  • ✓Create a new offset after changing device, microphone, browser, or audio processing settings

Important Notes

  • ⚠Calibration is stored locally on your device and browser
  • ⚠Clearing browser data will reset calibration
  • ⚠Different browsers on the same device may need separate calibration
  • ⚠Do not use the estimate for health, workplace, legal, or regulatory decisions