Decibel Level Chart

The decibel scale is logarithmic, not linear. This means that every 10 dB increase represents a tenfold increase in sound energy and roughly a doubling of perceived loudness. A sound at 80 dB is not "twice as loud" as 40 dB — it's actually 10,000 times more intense in terms of acoustic energy.

This logarithmic nature makes the scale compact enough to represent the enormous range of human hearing — from the threshold of perception at 0 dB to the threshold of pain above 120 dB. In practical terms, a 3 dB change is the smallest difference most people can detect. A 5 dB change is clearly noticeable. A 10 dB change sounds roughly twice as loud or half as loud.

When interpreting noise measurements, context matters as much as the number. A 50 dB reading in a bedroom at midnight feels intrusive, while the same level in a busy office goes unnoticed. Consider not just the absolute level but the environment, time of day, and duration of exposure when assessing whether a noise level is acceptable.

A simple rule of thumb: if you need to raise your voice to be heard by someone at arm's length, the ambient noise is likely above 80 dB, and hearing protection should be considered for prolonged exposure. At 85 dB — the level NIOSH uses as its recommended occupational exposure limit — the recommended maximum without protection is about 8 hours.

Foam earplugs provide 20–30 dB of attenuation and are the most practical option for everyday use. Over-ear earmuffs offer 25–35 dB of reduction and are preferred in industrial settings. For maximum protection in extremely loud environments (concerts, construction, shooting ranges), combining earplugs with earmuffs can provide 35–45 dB of attenuation.