Noise dose calculator
This page reports what the official source says. It is not legal advice: ask the office named here. Type the hours spent at each sound level to see the daily noise dose and the eight-hour average by the method in OSHA's rule at 29 CFR 1910.95. OSHA is the office named here.
Checked against the sources at the bottom of this page on October 8, 2026. Published tables are revised: the source has the last word.
Work it out
How the answer is worked out
For each row, the reference duration is T = 8 divided by 2 raised to the power (L minus 90) divided by 5, in hours, where L is the sound level in dBA. This matches OSHA's Table G-16a: 8 hours at 90 dBA, and the time halves with every 5 dBA more.
Dose D, in percent, = 100 times the sum of (hours at the level divided by T) over all rows.
Eight-hour time-weighted average = 16.61 times the base-10 logarithm of (D divided by 100), plus 90.
What the sources say
The OSHA rule at 29 CFR 1910.95 sets Table G-16 for sound measured on the A scale at slow response. Its footnote says that when a day's exposure has two or more periods at different levels, the combined effect is considered, and if the sum of the fractions C1/T1 + C2/T2 and so on exceeds 1, the mixed exposure is considered to exceed the limit value. It also says impulsive or impact noise should not exceed 140 dB peak sound pressure level.
The same rule requires a hearing conservation program when exposures equal or exceed an eight-hour time-weighted average of 85 decibels, or, equivalently, a dose of fifty percent, computed in line with Appendix A and Table G-16a and without regard to any attenuation from hearing protectors.
The rule's computation appendix, Appendix A, gives the dose formula and the average formula used here, with Table G-16a listing a reference duration for every level from 80 to 130 dBA. It gives two worked pairs: a dose of 91 percent is an average of 89.3 dB, and a dose of 50 percent is 85 dB. The calculator accepts levels from 80 to 130 dBA only.
OSHA also publishes a noise topic page that describes a permissible exposure limit of 90 dBA for an eight-hour day with a 5 dBA exchange rate, and says that noise in construction is covered by its own standards.
Table G-16, permissible noise exposures
| Duration per day, hours | Sound level, dBA, slow response |
|---|---|
| 8 | 90 |
| 6 | 92 |
| 4 | 95 |
| 3 | 97 |
| 2 | 100 |
| 1.5 | 102 |
| 1 | 105 |
| 0.5 | 110 |
| 0.25 or less | 115 |
Arithmetic only. The answer is only as good as the numbers entered. It is not a plan or a safe working load for any job.