The decibel (abbreviated dB) is the unit used to measure how loud a sound is. 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 sound that your ears can just barely hear. That's a big difference!

On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB. Below is a list of common sounds and their decibel levels, as well as some of our alarms for comparison.

50 dB    refrigerator 
50 - 75 dB washing machine
50 - 75 dB air conditioner 
50 - 80 dB electric shaver 
55 - 70 dB dishwasher 
60 - 85 dB vacuum cleaner 
60 - 95 dB hair dryer 
65 - 80 dB alarm clock 
75 - 85 dB flush toilet 
80 dB ringing telephone 
110 dB baby crying 
90 - 115 dB subway
95 - 110 dB motorcycle 
110 dB symphony concert 
110 dB car horn 
110 -120 dB rock concert 
112  dB CD player on high 
117 dB football game (stadium)
130 dB jackhammer, power drill 
130 dB MACE Personal Alarms
140 dB airplane taking off 
150 dB firecracker 
157 dB balloon pop 
162 dB fireworks (at 3 feet) 
163 dB rifle 
166 dB handgun 
170 dB shotgun

Here's a great link to a study done by Purdue University's Chemistry Department that charts sounds and their relative decibel measurements.

https://www.chem.purdue.edu/chemsafety/Training/PPETrain/dblevels.htm