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Mic Noise-Floor Meter

Measure the hiss under your voice, in dBFS, with the browser's processing switched off.

This measures the level your microphone produces when nothing is happening. Find somewhere quiet, then stay silent for six seconds. The audio is measured as it arrives and never recorded, stored or uploaded.

How this test works

The microphone is opened with echo cancellation, noise suppression and automatic gain all requested off, and then six seconds of your silence are measured. The tenth-percentile sample is taken as the floor rather than the average, so a single cough, keystroke or passing car becomes the loudest moment rather than the room's noise floor. Two things separate this from the browser sound meters it will be compared against. The number is dBFS, which describes the signal, because a sound-pressure level in dB SPL needs a calibrated microphone and any page printing one for your room is inventing it. And the applied settings are read back after the stream opens: browsers and operating systems can refuse to disable their processing, a floor measured through a noise suppressor is the suppressor's floor, and reporting that would tell someone with a hissy headset that their microphone is excellent. Where the request is refused, no figure is given.

What the results mean

Noise floor
The level your microphone produces when nothing is happening, in dBFS. More negative is quieter. Below −65 is very quiet, around −55 is good, and above −45 will be heard as a hiss in the gaps between words.
Loudest moment
The peak during the measurement. If it sits far above the floor, something happened while you were meant to be silent, and the run is worth repeating.
Browser processing
Whether the noise suppression and automatic gain were actually switched off. If they stayed on, the measurement is of the processing rather than the microphone, and the page says so instead of quoting a flattering number.
dBFS versus dB SPL
dBFS measures the signal relative to digital full scale. dB SPL measures sound pressure in the air and needs a calibrated microphone. Only the first is available to a web page, and the two are not interchangeable.

Common problems and fixes

The floor is high and the microphone is built into a laptop
That is largely inherent. The microphone sits inside the machine generating the fan noise and electrical noise, a few centimetres from both. Any external microphone, even a cheap headset, will usually improve it more than any setting will.
The result says the measurement was processed
Safari and several mobile browsers refuse to hand over an unprocessed stream. Chrome and Edge on desktop honour the request. There is no way for a page to force it, so the honest options are to switch browsers for the measurement or accept that the figure is unavailable here.
The floor rises when you speak more quietly
That is automatic gain reaching for the voice and lifting everything else with it. Move closer to the microphone and turn the input level down — using less gain is the single most effective change available.
It is worse on one USB port than another
Interference from a shared bus shows up exactly as a raised floor. Try a port on the other side of the machine and avoid unpowered hubs, then measure again.

Frequently asked questions

Why not show the level in decibels like a sound meter?

Because the number a sound meter shows is dB SPL, and producing one requires knowing how many volts your microphone puts out for a given sound pressure. That figure is a property of the specific microphone and is not exposed to a web page. Any browser tool printing a room level in dB is guessing at a calibration constant, and the guess can be wrong by twenty decibels or more.

Why does the browser's noise suppression matter so much?

Because it removes exactly what is being measured. A noise suppressor is designed to make a steady hiss disappear, so measuring through one reports how good the suppressor is, not how good the microphone is. Two microphones that differ enormously can produce nearly identical readings through it.

What is a good noise floor?

For speech, anything below about −55 dBFS will not be noticed at normal listening levels. A decent USB microphone in a quiet room reaches −65 or lower. Laptop microphones commonly sit between −50 and −40, which is audible but usable, and is what noise reduction in call software exists to handle.

Is my audio being recorded?

No. The level is computed from the stream as it arrives, sample by sample, and nothing is retained. The microphone is released the instant the six seconds end, and you can confirm it from the recording indicator disappearing.

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