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Real Decibel Meter

Browser Decibel-Meter Accuracy and Limitations

Your microphone was built for calls, not metrology. This page states plainly what the meter can and cannot claim.

Last materially reviewed: 2026-09-16

What the number means

The panel shows an uncalibrated browser estimate derived from Web Audio time-domain samples. Gain, placement, case resonance and frequency response differ per device, so two phones side by side can disagree by many decibels. Readings are never presented as approved, professional or lab-tested instrument results.

Why results differ between devices and browsers

  • Hardware variation: microphone capsules, preamp gain and placement differ across phones, laptops and headsets. Android devices vary especially widely.
  • Operating-system processing: the OS may apply gain or filtering before the browser ever sees samples.
  • Browser audio processing: echo cancellation, noise suppression and automatic gain control (AGC) reshape levels. This site requests them off via getUserMedia media constraints, but the browser or device may keep them enabled — the meter reports when that happens.
  • Mobile versus desktop: phones use aggressive voice processing and sit close to hands and pockets; laptops have noisier fans and more distant mics.

What calibration improves — and what it cannot fix

A calibration offset corrects overall gain against a reference you trust. It does not correct frequency response, distortion, clipping or processing that changes with level. A profile is device-specific: change the microphone, position, weighting or response and the old offset stops applying. See how to calibrate a browser decibel meter.

When a certified meter is required

Use a calibrated Class 1 or Class 2 sound level meter — not this browser estimate — for workplace noise assessment, legal disputes, hearing-safety verdicts, or any claim of compliance with IEC, ANSI, OSHA or NIOSH requirements. This site shows no safety verdicts for exactly this reason. Background on meter practice: CDC/NIOSH noise and sound guidance.

What improves a casual reading

  • Measure in a stable position at ear height, away from wind, vents and handling noise.
  • Use A-weighting for speech-like environments, C or Z when comparing spectra (dB vs dBA).
  • Let Fast/Slow smoothing settle for a few seconds before comparing with a decibel comparison chart.

Next: calibration → · Methodology → · Open the online decibel meter →