Device check / Sound
Sound Level Meter (Decibel Meter)
Measure how loud it is with your microphone: an estimated level in dB(A), the average, maximum, and minimum, and a chart of the last minute, with typical levels for comparison. Uncalibrated, so for comparison only.
Sound Level Meter (Decibel Meter): The page reads the microphone with the browser's voice processing turned off, so no automatic gain or noise suppression alters the level. The sound passes through an A-weighting filter, the standard curve that matches how the ear hears quiet sounds, then its level relative to the microphone's full scale is measured eight times a second. An offset turns that into an estimated sound level; the average is the energy average, Leq, as sound level meters report it. Runs 100% locally in your browser with zero server file uploads.
- Category
- Everyday tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Phone and computer microphones are not calibrated, so the decibel figures are estimates for comparison, not measurements. For hearing safety or legal limits, use a calibrated sound level meter.
- Average (Leq)
- — dB(A)
- Maximum
- — dB(A)
- Minimum
- — dB(A)
- Relative to full scale
- —
Calibrate
Estimated level = level relative to full scale + 100 dB. If you have a calibrated meter, measure the same steady sound with both and adjust this number until they agree.
Typical sound levels
- 30 dB(A) Whisper, quiet bedroom
- 40 dB(A) Quiet library
- 50 dB(A) Quiet office, rainfall
- 60 dB(A) Normal conversation
- 70 dB(A) Busy restaurant, vacuum cleaner
- 80 dB(A) Heavy traffic, alarm clock
- 85 dB(A) Hearing damage possible with long exposure
- 95 dB(A) Motorbike, loud concert nearby
- 110 dB(A) Rock concert, car horn close by
Getting useful readings
Hold the phone still, with the microphone, usually at the bottom edge, pointing at the sound and not covered by a case or hand. Measure for at least a minute and use the average, Leq, rather than a single reading. Wind on the microphone outdoors adds loud false readings.
To check that the microphone works at all, run the microphone test; to mask noise rather than measure it, try the white noise generator.
Why phones cannot be exact
A calibrated sound level meter has a measurement microphone with a known, flat response, checked against a reference source. Phone microphones are built for speech, vary from model to model, and stop at a maximum level, so loud sounds above about 100 dB may read too low.
How to use it
- Press Start measuring and allow the microphone.
- Read the current level, the average (Leq), and the maximum and minimum, and watch the chart.
- If you have a calibrated meter, adjust the offset under Calibrate so the two agree.
Privacy & limitations
The microphone is analysed in your browser; nothing is recorded or sent anywhere.
Related tools
Frequently asked questions
How accurate is a phone decibel meter?
Without calibration, readings can be several decibels off, more at very low and very high levels, because each phone's microphone and processing differ. It is good for comparing, such as one room with another, or before and after soundproofing, but not for legal or safety measurements.
What does dB(A) mean?
Decibels with A-weighting, which reduces low and very high frequencies the way human hearing does at moderate levels. Noise limits for workplaces and neighbourhoods are usually given in dB(A).
How loud is too loud?
Long or repeated exposure above about 85 dB(A) can damage hearing; workplace limits are often 85 dB(A) averaged over eight hours. Every 3 dB more halves the safe listening time.
What is Leq?
The equivalent continuous level: the steady level with the same total sound energy as the varying sound measured. Loud moments count for more than in a simple average, because decibels are logarithmic.
Free tool · runs in your browser · no account required