About dB Meters
dB Meters is a free sound level meter that runs in your web browser. It turns your phone or computer microphone into a decibel meter, and adds what a basic noise app leaves out: proper A, C and Z frequency weighting, the true energy average (Leq), percentiles, a spectrum, a hearing-safety dose and a log you can export. It's available in 16 languages.
How it works
The page asks the browser for the raw microphone signal, with echo cancellation, noise suppression and automatic gain control switched off, because those features would change the level. Every sample then runs through digital filters built from the IEC 61672 A and C weighting curves. The filters follow the standard to within a few hundredths of a decibel below 1 kHz and stay inside Class 1 tolerances up to 16 kHz, and they're covered by automated tests.
Levels are time-weighted with the standard Fast (125 ms), Slow (1 s) and Impulse responses. The average is the energy average, not an average of decibel numbers, and the noise dose follows the NIOSH recommendation of 85 dBA for 8 hours with a 3 dB exchange rate.
What we care about
- Honest readings. Until you calibrate, readings are labelled as estimates. If the sound is too loud for the microphone, the meter says so.
- Private by design. Audio is analysed on your device and immediately discarded. Nothing is recorded or uploaded. See the privacy policy.
- Fast and light. No frameworks and no app to install. It works offline once loaded.
- Accessible. Large readouts, keyboard support and a dark theme.
Limits
A phone microphone isn't a certified measuring instrument. Calibrated, it's typically within a couple of decibels in the middle of its range; uncalibrated, it can be further out. For legal, workplace or environmental assessments, use a certified Class 1 or Class 2 sound level meter.
Contact
Spotted a mistake, or have a suggestion? Email hello@dbmeters.com.