Occupational Noise Exposure Limits
Computes the allowable daily exposure time for a sound level under both the NIOSH and OSHA noise limits, and returns both.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Measured sound level, dBA
- 100 dBA
Result: 15 min allowed under NIOSH and 2 h under OSHA
The tool opens with these values already filled in. Replace them with your own.
What the result means
- NIOSH
- 85 dBA for eight hours, with a 3 dB exchange rate. Allowable minutes are 480 divided by 2 to the power of the level minus 85, over 3.
- OSHA
- 90 dBA for eight hours, with a 5 dB exchange rate. Allowable hours are 8 divided by 2 to the power of the level minus 90, over 5.
- Why they differ
- Different limits and different exchange rates. At 100 dBA that is fifteen minutes under NIOSH and two hours under OSHA, and neither is quoted here as the answer.
- The OSHA number
- A legal ceiling, not a safety threshold. The NIOSH figure is the health-based recommendation, so meeting the law may still be well past what protects hearing.
- The action level
- An eight-hour average at or above 85 dBA requires a hearing conservation program under OSHA. Whether the average reaches it depends on the whole day.
- Hearing protectors
- A label rating is derated as the rating minus 7, halved, for an A-weighted measurement. A protector marked 33 dB is credited with 13 dB.
What you enter
- Measured sound level, dBA
- Exposure duration, hours
- Hearing protector noise reduction rating on the label, dB (derated as rating minus 7, halved)
How this is calculated
NIOSH. Criteria for a Recommended Standard: Occupational Noise Exposure, Revised Criteria 1998. DHHS (NIOSH) Publication No. 98-126. OSHA. Occupational noise exposure, 29 CFR 1910.95. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.