Sound Level Meter

Measures how loud it is around you through your phone or computer microphone, as a number, a bar and a 60-second graph. Use it to compare which place or moment is louder on the same device.

How to use

1. Press "Turn on microphone" and allow access when the browser asks.
2. Read the "Relative level" (0 to 100) and the "Digital level" in dBFS. The graph and the minimum, average and maximum show the changes.
3. Under "Response", choose "Fast (0.125 s)" for short sounds or "Slow (1 s)" for steady noise.
4. Press "Reset min, max and average" to start a new comparison.

How it works

• Phone and computer microphones are not calibrated, so these numbers are not real decibels (dB SPL), and another device can read the same sound differently.
• dBFS is a digital level where 0 is the loudest the microphone input can record, calculated as 20 × log10(RMS). Relative level 0 is −80 dBFS and 100 is 0 dBFS, with no A-weighting.
• If you have a reference meter, enter meter dB − screen dBFS under "Enter a calibration offset" to also see an approximate dB value.
• It is not for disputes, noise complaints or workplace assessments. Microphone sound is not recorded or sent.

Questions and answers

Is a phone decibel meter accurate?

Not as real dB values, because the microphone is not calibrated. Use it to compare sounds on the same device; for accurate values, use a certified sound level meter.

Can I use it to measure noise from my neighbours?

It shows when the noise gets louder and by how much, but it cannot serve as evidence in a complaint or dispute. That needs a certified sound level meter.

Why is the dBFS value negative?

dBFS sets the loudest sound the microphone can record to 0, so quieter sounds are negative. −20 dBFS is 20 dB louder than −40 dBFS.

How do I find the calibration offset?

Measure a steady sound, such as a fan, with a reference meter placed next to the microphone. If the meter shows 55 dB and the screen −40 dBFS, the offset is 95.