Sound Level Meter

Live decibel readings from your microphone, with honest calibration limits.

Press Start, allow microphone access, and this page shows a live sound level from your device microphone. Browsers do not hand a web page a calibrated sound-pressure reading, so the meter shows the raw microphone level in dBFS and an estimated dB SPL figure built from an editable calibration offset. The offset is a guess until you calibrate it against a known sound, and the page says so plainly. Audio is processed in your browser and never recorded or sent anywhere.

Calibration offset (dB) - added to the raw microphone level

Default 90 is a starting guess only. In a normal conversation at arm's length, adjust it until the meter reads about 60. A real meter is the only way to calibrate properly.

Display smoothing

-- dB (estimated)

Raw microphone level: -- dBFS | Peak: -- dB | Minimum: -- dB

Press Start and allow microphone access.

Honest limits. This is an estimate, not a certified sound level meter: microphone sensitivity differs by device, browsers apply their own gain and noise processing, and the offset above is uncalibrated by default. Do not use it for workplace noise compliance, legal evidence or hearing-safety decisions. A sustained reading above 85 dB on a calibrated meter is the commonly cited hearing-risk line; on this uncalibrated page, treat any high reading as a reason to check with a real meter, not as a measurement. Reference sounds: whisper about 30 dB, normal conversation about 60 dB, city traffic about 80 to 85 dB. Audio is never recorded, stored or uploaded.

What a decibel actually measures

A decibel is a logarithmic unit: it expresses a sound as a ratio against a reference, not as an absolute amount. That is why the scale behaves strangely. A 10 dB rise means ten times the sound energy, and it feels roughly twice as loud, so the gap between a quiet room at 30 dB and a conversation at 60 dB is far bigger than the numbers suggest: a thousand times the energy. Sound pressure level, written dB SPL, is measured against the quietest sound an average ear can hear, which is set at 0 dB. A web page cannot read dB SPL directly, because the browser only reports how loud the signal is relative to the microphone's own full scale, written dBFS, where 0 is the loudest the microphone can report and everything else is negative.

The calibration offset bridges those two scales. If a normal conversation reads minus 30 dBFS on your device, and a real conversation is about 60 dB SPL, then the offset is 90, and the estimate is the raw reading plus 90. The offset is device-specific: the same room reads differently on a phone and a laptop, and moving the device changes the reading, because sound falls off with distance. Calibrate in the room you will measure in, at the distance you will measure from, and re-check whenever you switch devices.

Reference sounds

Whisper about 30 dB, quiet library about 40 dB, normal conversation about 60 dB, vacuum cleaner about 70 dB, city traffic about 80 to 85 dB. Hearing-risk guidance commonly cites 85 dB as the level where sustained exposure starts to matter, which is why a vacuum cleaner all day is a different matter from a vacuum cleaner for ten minutes.

Why browsers limit the reading

Browsers add echo cancellation and noise suppression to microphone input by default, and this page asks for them to be turned off, but a browser or device may still apply its own processing. That processing can squash loud peaks and lift quiet rooms, which is another reason the figure is an estimate. If your device reports silence in a noisy room, check its microphone permission and whether another app holds the microphone.

Frequently Asked Questions

It is an estimate. Browsers report microphone level relative to full scale (dBFS), not calibrated sound pressure (dB SPL). This page converts with an editable offset, which is a guess until you calibrate it against a known sound or a real meter. Do not use it for workplace compliance, legal evidence or hearing-safety decisions.

Put the device where you will measure, hold a normal conversation at arm's length, and adjust the offset until the meter reads about 60 dB. A real sound level meter gives a proper calibration; without one, the reading is only comparable with itself on the same device.

Microphone sensitivity differs by device, and browsers apply their own gain and noise processing. The offset is device-specific, so calibrate each device separately and note which device a reading came from.

About 30 dB is a whisper, 40 dB a quiet library, 60 dB normal conversation, 70 dB a vacuum cleaner, and 80 to 85 dB city traffic. Sustained exposure above 85 dB is the commonly cited hearing-risk line on a calibrated meter.

No. The microphone signal is analysed in your browser and discarded. Nothing is recorded, stored or uploaded, and stopping the meter releases the microphone.

Usually a microphone permission problem, another app holding the microphone, or the device's own noise processing. Check the permission, close other apps using the microphone, and try again.