A decibel (dB) is a logarithmic unit used to measure sound intensity or loudness. Because the decibel scale is logarithmic, an increase of 10 dB represents a 10-fold increase in sound intensity, but the human ear perceives it as roughly twice as loud. For example, 60 dB sounds about twice as loud as 50 dB, even though the sound energy is 10 times greater. The decibel scale typically ranges from 0 dB (the threshold of human hearing) to around 140 dB (the pain threshold).

Sounds below 70 dB are generally considered safe for unlimited exposure. According to NIOSH, sounds at or above 85 dB can cause hearing damage with prolonged exposure. The safe listening time is cut in half for every 3 dB increase above 85 dB. The World Health Organization recommends keeping environmental noise below 70 dB over a 24-hour period and below 75 dB over an 8-hour period to prevent hearing impairment.

It depends on the volume level. At 85 dB, you can listen safely for up to 8 hours. At 100 dB (typical at concerts), safe exposure drops to just 15 minutes. At 110 dB (nightclubs, loud concerts), damage can occur in under 2 minutes. A good rule of thumb: if you need to raise your voice to be heard by someone an arm's length away, the noise level is likely above 85 dB and potentially harmful over time. Always use hearing protection at concerts and consider the 60/60 rule for headphones: listen at no more than 60% volume for no more than 60 minutes at a time.

While a 10 dB increase means the sound intensity is 10 times greater, the human ear perceives it as approximately 2 times louder. This is due to the ear's non-linear response to sound pressure levels (described by the Fletcher-Munson curves). So going from 50 dB (normal conversation) to 60 dB (office noise) — the sound energy is 10x higher, but your brain interprets it as roughly twice as loud.

Common symptoms include: tinnitus (ringing, buzzing, or hissing in the ears), difficulty understanding speech in noisy environments (the "cocktail party problem"), muffled hearing, needing to turn up the volume on TV or phone, and a sensation of fullness or pressure in the ears. Hearing loss from noise damage is often gradual and painless, affecting high frequencies first. If you experience ringing in your ears after loud noise exposure, your hearing has already been temporarily damaged, and repeated exposure can make it permanent.

1. Wear earplugs or earmuffs: Foam earplugs can reduce noise by 20–30 dB when properly inserted. Earmuffs offer similar protection.
2. Follow the 60/60 rule for headphones: 60% volume, 60 minutes max at a time.
3. Take listening breaks: Step away from loud environments periodically — your ears need recovery time.
4. Keep distance from sound sources: Doubling your distance from a point sound source reduces sound level by about 6 dB.
5. Use noise-canceling headphones: They allow lower listening volumes in noisy environments by reducing background noise.
6. Get regular hearing checkups: Early detection of hearing loss can help prevent further damage.

The pain threshold for human ears is approximately 120–130 dB. At 120 dB (e.g., a jet engine at close range), sound becomes physically uncomfortable. At 130 dB, most people experience actual pain. At 140 dB (gunshot, fireworks at close range), even a single brief exposure can cause permanent hearing damage. Sounds above 150 dB can rupture the eardrum. The loudest sound possible at sea level is approximately 194 dB, at which point sound waves become shock waves.