How to Use the Noise Exposure Time Calculator
The louder the noise, the shorter you can be exposed to it without risking hearing damage. This calculator applies OSHA's permissible exposure limit (PEL) using the standard "5 dB exchange rate." The reference point is 8 hours at 90 dB, and the allowed exposure time is cut in half for every 5 dB increase — 95 dB allows 4 hours, 100 dB allows 2 hours, and 105 dB allows just 1 hour.
Conversely, the allowed time doubles for every 5 dB decrease, and OSHA treats noise under 80 dB as relatively safe without a strict daily limit. Anything above 115 dB is considered hazardous even briefly, so exposure should be avoided entirely.
Construction sites, concerts, and loud headphone listening can all push past 90 dB without you realizing it. Use this calculator to check your safe exposure window ahead of time, and wear hearing protection such as earplugs whenever loud conditions are expected — it's one of the simplest ways to prevent noise-induced hearing loss.
Frequently Asked Questions
It's OSHA's rule that for every 5 dB increase in noise, the allowed exposure time is cut in half. If 90 dB allows 8 hours, 95 dB allows 4 hours and 100 dB allows only 2 hours.
Not instantly, but the risk of noise-induced hearing loss rises with cumulative exposure. Try to stay within the allowed time and wear hearing protection like earplugs in loud environments.