Decibel Meter

People who want to know how loud the noise from next door, upstairs, a road or a construction site really is. Anyone who wants a record of times and levels before talking to a landlord, building manager or the local authority. Musicians and parents wondering how much sound gets outside. People who want a rough idea before buying a sound level meter.

No. This decibel meter works in your browser with your phone or computer microphone. Press “Start measuring” and allow the microphone. Readings are an estimate, so use a dedicated sound level meter when you need exact figures.

It's an estimate. Phone and computer microphones aren't calibrated like a sound level meter, so the same sound can read several dB to more than 10 dB differently on different devices. When you need exact figures, use a dedicated sound level meter.

Measure the same sound next to a real sound level meter or an app you trust, then enter the number to add or subtract in “Calibration” until the readings match. The value is saved in this browser on this device and used next time.

dB(A) uses A-weighting, which counts very low and very high sounds less, the way human hearing does. It's what most noise guidelines use. dB(Z) has no frequency weighting. In most cases, leave it on dB(A).

The one-second values are averaged by sound energy (the same idea as an equivalent continuous sound level, Leq). A few loud moments raise it more than a simple average of the numbers would.