Noise Exposure Calculator

About the Noise Exposure Calculator

Noise-induced hearing loss is one of the most common occupational health hazards and is entirely preventable. This calculator shows the maximum safe exposure time at any decibel level based on both OSHA (Occupational Safety and Health Administration) and NIOSH (National Institute for Occupational Safety and Health) standards. Understanding these limits helps protect your hearing at work, at concerts, and in daily life.

OSHA vs NIOSH Standards

OSHA uses a 5 dB exchange rate with a 90 dB reference: for every 5 dB increase above 90, the permissible exposure time halves. At 90 dB you get 8 hours, at 95 dB you get 4 hours, at 100 dB you get 2 hours. NIOSH uses a more conservative 3 dB exchange rate with an 85 dB reference: at 85 dB you get 8 hours, at 88 dB you get 4 hours, at 91 dB you get 2 hours. At 100 dB, OSHA allows 2 hours while NIOSH allows only about 15 minutes. NIOSH standards are considered more protective and are recommended by hearing health professionals.

The Decibel Scale

Decibels use a logarithmic scale, so a 10 dB increase represents a tenfold increase in sound intensity. Normal conversation is about 60 dB. A lawn mower is 85 dB. A rock concert hits 100-115 dB. A jet engine at close range reaches 140 dB. Even brief exposure to sounds above 120 dB can cause immediate, permanent hearing damage. The logarithmic nature means that 100 dB is not twice as loud as 50 dB but rather 100,000 times more intense.

Common Noise Sources and Their Levels

Understanding common noise levels helps you assess risk. A whisper is about 30 dB. Normal conversation sits around 60 dB. City traffic from inside a car reaches about 80-85 dB. A motorcycle engine at close range is 90 dB. Power tools like drills and saws range from 95 to 110 dB. Concert speakers near the stage can exceed 115 dB, and firearms produce impulse noise of 140-170 dB. Even household appliances like blenders (80-90 dB) and hair dryers (80-90 dB) can contribute to cumulative exposure over time.

Protecting Your Hearing

Prevention is the only cure for noise-induced hearing loss. Wear hearing protection whenever you expect exposure above 85 dB. Foam earplugs are inexpensive and reduce noise by 15-30 dB. Over-ear earmuffs provide 20-35 dB reduction. For extremely loud environments, combine both. Follow the 60/60 rule for headphones: no more than 60% volume for 60 minutes at a time. If you work in a noisy environment, your employer is required by OSHA to provide hearing protection and regular hearing tests.