What this calculator does
Safe noise exposure time works out maximum daily exposure time allowed at a given noise level, NIOSH or OSHA rules. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaT = 8 ÷ 2^((L − L0) ÷ E) hours, where L0 and the exchange rate E are 85 dB / 3 dB (NIOSH) or 90 dB / 5 dB (OSHA)
The inputs explained
| Field | What to enter |
|---|---|
| Noise level (dBA) | A number, measured in dBA. Starts at 95. |
| Standard | Choose from NIOSH (85 dB, 3 dB exchange), OSHA (90 dB, 5 dB exchange). |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with noise level
Every other input is held at the calculator’s starting values while noise level varies. Select any row to load that scenario into the calculator.
How the answer changes with noise level
| Noise level (dBA) | Maximum daily exposure | Reference level | Exchange rate |
|---|---|---|---|
| 47.5 | Unlimited (over 24 h) at this level | 85 dBA for 8 hours | Halves every 3 dB increase |
| 71.25 | Unlimited (over 24 h) at this level | 85 dBA for 8 hours | Halves every 3 dB increase |
| 95 | 0 h 47 min | 85 dBA for 8 hours | Halves every 3 dB increase |
| 143 | 0 h 0 min | 85 dBA for 8 hours | Halves every 3 dB increase |
| 190 | 0 h 0 min | 85 dBA for 8 hours | Halves every 3 dB increase |
| 285 | 0 h 0 min | 85 dBA for 8 hours | Halves every 3 dB increase |