Free calculator
Work out a crew's daily noise dose.
List the noise levels people work in and how long they spend in each. You'll get the dose and the 8-hour average, and whether it crosses OSHA's action level or limit.
Also calledNoise dose calculator, Time-weighted average noise calculator, OSHA noise calculator
Noise levels and how long you’re exposed to each
Result
Noise dose
--%
8-hour average
--dBA
Uses OSHA’s method: a 90 dBA limit over 8 hours with a 5 dB exchange rate, ignoring sound below 80 dBA. Measure with a calibrated meter and check the current standard and your hearing conservation program.
How long can someone stay at one level?
Enter a level of 90 dBA or more.
This does arithmetic on what you type. Nothing leaves your browser. Check the result against your own rules and procedures.
How it's calculated
- Allowed time at a level: T = 8 ÷ 2^((L − 90) ÷ 5) hours, where L is the level in dBA.
- Dose = the sum of (hours at each level ÷ allowed hours at that level).
- 8-hour average = 16.61 × log10(dose) + 90 dBA, with the dose as a fraction of 1.
- Following OSHA, sound below 80 dBA isn't counted.
What to do with the number
- OSHA's permissible exposure limit is a 90 dBA 8-hour average (a 100% dose). Its action level is an 85 dBA average (a 50% dose), where a hearing conservation program applies. NIOSH recommends a lower limit. Measure with a calibrated meter or dosimeter, and check the current standard and your own program.
Run this in the field.
Log noise readings and hearing protection checks from a phone, with the record kept for you.
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Common questions
- What is noise dose?
- It's the share of the daily limit that a person's exposure uses up. 100% is the permissible exposure limit. 50% is the OSHA action level.
- What is an exchange rate?
- It's how much the level can rise before the allowed time halves. OSHA uses 5 dB. NIOSH uses 3 dB, which is more protective.
- Does this replace noise monitoring?
- No. It does the arithmetic on numbers you've measured. Use a calibrated sound level meter or a personal dosimeter, and follow your hearing conservation program.
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