Hearing Damage Risk Calculator
Estimate safe noise exposure time from sound level in decibels using NIOSH and OSHA guidelines. 85 dB safe for 8 hrs (NIOSH), 90 dB for 8 hrs (OSHA).
Noise-induced hearing loss is one of the most common occupational hazards and recreational risks worldwide.
NIOSH (National Institute for Occupational Safety and Health) recommends a maximum exposure of 85 decibels (dB) for 8 hours. For every 3 dB increase above 85 dB, the safe exposure time is cut in half.
Safe exposure time formula (NIOSH):
T = 8 / (2 ^ ((dB - 85) / 3)) hours
Common noise levels:
- Normal conversation: 60-70 dB (safe)
- Vacuum cleaner: 70 dB (safe)
- City traffic from inside car: 80-85 dB (8 hours max)
- Lawn mower: 90 dB (about 2.5 hours)
- Concert or nightclub: 100-110 dB (minutes only)
- Chainsaw: 110 dB (about 1.5 minutes)
- Fireworks at close range: 140-160 dB (immediate damage)
OSHA (Occupational Safety and Health Administration) uses a slightly more lenient standard with a 5 dB exchange rate. NIOSH uses a 3 dB exchange rate, which is considered more protective and is used in this calculator.
Hearing protection reduces effective noise exposure. Foam earplugs typically reduce noise by 20-30 dB. Over-ear muffs reduce noise by 25-35 dB. Using both together can provide 30-40 dB reduction.
Key facts:
- Hearing damage is cumulative and permanent.
- Ringing in the ears (tinnitus) after exposure is a warning sign.
- Regular hearing checks are recommended for anyone exposed to loud environments.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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