Decibel turns your phone or laptop microphone into a noise level meter.
Sound never leaves the device — no recording, no upload, no analytics.
Useful for finding a quiet café, sanity-checking a noisy commute,
or knowing when a room has slipped past the threshold where hearing starts to suffer.
Sound Level Meter · SL·26·002Calibration · approximate · A-weighted
—dB SPL
Awaiting input
Peak
—dB
Mean · 60 s
—dB
Lmin
—dB
Elapsed
00:00
Live waveform± normalized
Last 60 seconds
dB SPL · 10 readings / sec
−60 s−45−30−15now
Before you press start
Your browser will ask for microphone access. If you allow it, audio is read
locally to compute a level in decibels. Nothing is recorded, transmitted, or
kept after you close the tab.
Readings are an estimate. Phones aren't calibrated instruments — treat ±5 dB as honest.
Hold the device still and away from clothing for stable numbers.
Sustained exposure above 85 dB damages hearing. Brief peaks are usually fine.
Works offline once loaded. Save the page if you'd like a portable copy.
Reading the zones
< 50 dB
Quiet
Library, bedroom at night, soft conversation across a room.
50 – 70 dB
Conversational
Cafés, offices, kitchens. Comfortable for thinking and talking.
70 – 85 dB
Loud
Busy restaurants, vacuums, city traffic. Tiring for long stretches.
> 85 dB
Hearing risk
Sustained exposure damages hearing. Concerts, motorbikes, power tools.
How it measures
The meter reads short windows of audio from your microphone, computes the
root-mean-square amplitude of each window, converts that to decibels relative
to full scale, and offsets the result by a fixed reference so the displayed
number lands near real-world dB SPL.
Without a calibrated reference signal, the offset is a heuristic — accurate
enough to compare two rooms, not accurate enough to file a noise complaint.
What it doesn't do
It doesn't record. It doesn't upload. It doesn't fingerprint your device. The
only network requests this page ever makes are for the two fonts at the top
of the file. You can block them and it still works.
It also won't replace a class-1 sound level meter, and shouldn't be used to
certify a workplace. For that, hire an acoustician.