About
About dB Meter Online
A free, browser-based decibel meter with plain-English guides. Here is how it works and where our numbers come from.
What it is
dB Meter Online is a free online decibel meter. It runs in your web browser on a phone, tablet or computer, with no app, account or sign-up, plus short guides to everyday sound levels, the decibel scale and safe decibel levels.
How the reading is calculated
After you tap Start, the page reads raw microphone samples with the Web Audio API (echo cancellation, noise suppression and auto-gain switched off where the browser allows). It calculates the RMS level in dBFS, adds a fixed +94 dB offset plus your calibration offset to estimate dB SPL, and applies energy-based Fast (125 ms) or Slow (1 s) time weighting. The session average is the energy average (Leq). Readings are unweighted (not dBA) and clamped to 0–130 dB.
What it can’t do
It is not a certified sound level meter or noise dosimeter. Browsers don’t reveal microphone sensitivity, so uncalibrated readings can be off by several dB or more. Don’t use it for legal, workplace-compliance or medical decisions. The guides are general information, not medical advice.
Who we are
An independent small website. We are not affiliated with NIOSH, the WHO or any phone or meter maker. The pages are written from the published sources listed below; they have not been reviewed by an audiologist. The meter is free; an iPhone app is planned but not available yet.
How we handle your data: see the privacy page (short version: microphone audio never leaves your device).
Sources
- CDC / NIOSH: Noise and Hearing Loss (recommended exposure limit, 85 dBA / 8 h, 3 dB exchange rate)
- NIDCD (US National Institutes of Health): Noise-Induced Hearing Loss
- WHO–ITU: Safe listening devices and systems (H.870 standard)
- WHO: Global standard for safe listening venues and events
- WHO Regional Office for Europe: Environmental Noise Guidelines (2018)
- Purdue University: Noise Sources and Their Effects
- American Speech-Language-Hearing Association: Safe Listening infographic (2022)