What is a decibel, and how is it measured?

The decibel (abbreviated dB) is the unit used to measure the intensity of a sound. The decibel scale is a little odd because the human ear is incredibly sensitive. Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet engine. In terms of power, the sound of the jet engine is about 1,000,000,000,000 times more powerful than the smallest audible sound. That's a big difference!

Humans can hear sounds between 0 and 140 decibels.  0 decibel does not mean that there is no sound, merely that we cannot hear it. 0 decibel is the so-called hearing threshold for the human ear. While we can hear more than 140 decibels, it is too painful for our ears and if you expose yourself to such a loud noise you are at extremely high risk of permanent damage to your hearing. The table below shows how loud sound is.

Decibel meter

According to United Kingdom legislation you are obliged to wear hearing protection if you work in an environment with 80 decibels of sound or higher on a daily basis. For fun, check out the following decibel meter. 

Example of decibels