Decibel meter, in your browser.
Press Start, allow the microphone, and read the sound level in dB(A). The number is not calibrated, so use it as a guide, not as proof. Nothing is recorded or sent.
Free · runs in your browser · nothing is sentPress Start
- Min
- –
- Avg
- –
- Max
- –
Not calibrated
The meter asks for the microphone. Nothing is recorded or sent.
How to use it
- Press Start meter and allow the microphone. The sound is turned into a number in your browser; nothing is recorded or sent.
- Hold the phone still, microphone towards the sound, about a metre away. Do not cover the microphone with a finger or a case.
- Read the number. Fast follows what you hear right now; Slow shows the level over the last second, which is easier to read. Min, Avg and Max add up until you press Reset.
If you have a sound level meter you trust, hold the phone next to it and use −1 dB and +1 dB until the two agree. The offset is not saved.
What the number means
The line under the number is the same comparison the Sound Meter app shows. It is a rough guide, not a limit.
| dB(A) | Like |
|---|---|
| Under 30 | A whisper |
| 30 to 44 | A quiet room |
| 45 to 64 | Normal talk |
| 65 to 74 | A vacuum cleaner |
| 75 to 84 | A busy street |
| 85 to 94 | A lawn mower |
| 95 to 104 | A loud concert |
| 105 and up | A chainsaw |
Decibels are a log scale: 10 dB more is ten times the sound energy. So the step from 65 to 75 is a much bigger change than it looks.
How far to trust it
A phone microphone is made for calls, not for measuring. Android's compatibility rules (CDD 5.4.2) ask phone makers for a flat response within ±3 dB from 100 Hz to 4 kHz, and a set sensitivity: a 90 dB tone should give −22.35 dBFS, ±3 dB. Both are written as "SHOULD", not "MUST", so a phone may do worse. The page uses that sensitivity as its starting point, which is why it says not calibrated.
A browser adds its own unknowns. The page asks it to turn off echo cancellation, noise suppression and auto gain, but not every browser listens, and a laptop microphone follows no rule at all. So the page tells you when it cannot measure: ≤ 30 when the sound is below what the microphone can hear, and ≥ in front of the number when the samples clip, because the real level is at least that much. If the microphone stops, the page says so instead of leaving an old number on the screen.
For a number you can act on, calibrate next to a meter you trust, and use a certified sound level meter for anything legal or at work.
Why the app, if the page works?
A browser stops reading the microphone when the screen locks or you switch apps, and it forgets your calibration when you close the tab. It also cannot tell you much about the microphone it is using.
The Sound Meter app keeps the same honest number, and adds the things a page cannot do: a noise log that runs up to 24 hours with the screen off, one reading a second, with a Stop button in the notification (Pro); a calibration it keeps; a 60-second graph; and a spectrum from 31.5 Hz to 16 kHz (Pro). In our test on a Galaxy S23 it logged for 61 minutes with the screen off and in deep sleep, with no gaps. It never records sound, only the numbers. No ads, no subscription.
Questions
Is this decibel meter free?
Yes. No account, no ads, nothing to install. It saves nothing, not even the offset you set: the page starts fresh each time.
How accurate is it?
It is not calibrated, so treat it as a guide. Android asks phone makers to keep the microphone within ±3 dB from 100 Hz to 4 kHz, but as a recommendation, not a rule. A browser can add its own processing, and laptops follow no such rule. Set the offset next to a meter you trust and the number gets closer. For legal or workplace limits you need a certified sound level meter.
Why does it show ≤ 30 or ≥ a number?
Phone microphones cannot hear very quiet sounds, and they clip when it is very loud. When the sound is below what the microphone can measure, the page shows ≤ 30 instead of guessing. When the samples clip, it shows ≥ in front of the number: the real level is at least that much.
Does it work on a laptop?
Yes, with the built-in microphone, but laptop microphones are made for calls, not for measuring. The browser may also turn on noise suppression and auto gain that the page cannot switch off. Expect a bigger error than on a phone.
Is anything recorded or sent?
No. The sound stays in your browser, where the page turns it into one number at a time. Nothing is saved or sent, and the microphone is released when you press Stop or leave the tab.
What does the (A) in dB(A) mean?
A-weighting. It counts low and very high frequencies for less, the way the ear does, so a 100 Hz hum adds less to the number than a 1 kHz tone. Sound level meters and noise rules use dB(A), so the page does too.