The noise exposure calculator is based on OSHA criteria.

Noise Exposure Calculator (OSHA Standards)

OSHA's maximum allowable daily 8-hour TWA with protection is 90 dBA or 100% noise dose.

TWA: Time-weighted Average



The formula used to calculate the noise dose based on OSHA criteria is part of the noise dose calculation for occupational exposure. OSHA (Occupational Safety and Health Administration) sets limits on exposure to sound levels in the workplace to protect workers from hearing loss. The formula used for calculating the noise dose, considering the maximum allowable daily 8-hour Time Weighted Average (TWA) exposure level, is:



  • 𝐢1,𝐢2,…,𝐢𝑛 are the total exposure times at different noise levels during the workday.
  • 𝑇1,𝑇2,…,𝑇𝑛 are the corresponding allowable exposure times at those noise levels according to OSHA's standards.

- Occupational Safety and Health Administration Appendix A to Β§ 1910.95 - Noise Exposure Computation.



The Occupational Safety and Health Administration is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces.
Established by the Occupational Safety and Health Act of 1970, OSHA opens its doors on April 28, 1971. OSHA requires employers to implement a hearing conservation program when noise exposure is at or above 85 decibels averaged over 8 working hours, or an 8-hour time-weighted average (TWA).


  • Noise Exposure or Sound Level: The average sound level measured for the worker at this location.
  • Duration or Exposure Time: The length of time that the worker spends at this location each day.
  • 8-Hour Time-Weighted Average: Average noise exposure figured for an 8-hour period.
  • Permissible Exposure Level (PEL): Maximum allowable 8-hour TWA noise exposure (OSHA's limit is 90 dBA).
  • Noise Dose: Percent of PEL to which worker exposed. 90 dBA 8-hour TWA equals a dose of 100%. An 85 dBA 8-hour TWA equals 50%. The exchange rate is used to figure this.
  • Exchange Rate: Amount of dBA at which noise dose doubles. OSHA uses a 5 dBA exchange rate which means that a worker exposed to 95 dBA receives twice the dose of 90 dBA.
  • Noise dosimeters: Devices used in sound surveys to calculate noise exposure.