What Is a Decibel (dB)?
The decibel (dB) is a logarithmic unit used to measure sound intensity. It is based on the quietest sound a human can hear (0 dB). Every 10 dB increase means the sound energy is 10 times greater, and sounds roughly twice as loud to human ears. A 20 dB increase equals 100× more sound energy.
Everyday Noise Levels
| Level (dB) | Examples | Hearing Risk |
|---|---|---|
| 0–30 dB | Silent studio, deep forest | None |
| 31–55 dB | Whisper, quiet library | None |
| 56–70 dB | TV, restaurant conversation | Low |
| 71–85 dB | Subway, blender | Caution |
| 86–100 dB | Concert, motorcycle | Dangerous |
| 101–120 dB | Jackhammer, fireworks | Immediate damage risk |
| 121+ dB | Gunshot, jet engine | Severe immediate damage |
NIOSH Hearing Protection Guidelines
The National Institute for Occupational Safety and Health (NIOSH) sets 85 dB as the maximum safe level for 8-hour daily exposure. Safe exposure time halves with every 3 dB increase: 88 dB → 4 hours, 91 dB → 2 hours, 100 dB → 15 minutes, 110 dB → about 1 minute.
Safe Listening Habits
Earbuds at full volume can reach 100–110 dB. The WHO recommends the 60-60 rule: keep volume at 60% or below and limit listening to 60 minutes per day. In noisy environments, use noise-canceling headphones instead of turning up the volume.
Frequently Asked Questions
According to NIOSH, prolonged exposure to 85 dB or more can cause hearing damage. At 85 dB, 8 hours per day is the recommended maximum. Safe exposure time halves with every 3 dB increase.
Earbuds at full volume can reach 100–110 dB. The WHO recommends keeping volume at 60% or below and limiting daily listening to 60 minutes.
Every 3 dB increase doubles the sound energy. A 10 dB increase sounds roughly twice as loud to human ears. A 20 dB increase means 100× more energy.