Daily Noise Dose Calculator
Work out what percentage of your safe daily noise limit an exposure uses up, using the NIOSH 3 dB rule.
Enter the sound level and how many hours you get it.
How a Daily Noise Dose Works
Hearing damage is cumulative and dose-dependent, which is why the useful question is not “is this loud?” but “how much of today’s budget did that use?”
NIOSH (National Institute for Occupational Safety and Health) and OSHA (Occupational Safety and Health Administration) both express that budget as a time-intensity trade-off: every 3 dB increase (NIOSH) or 5 dB increase (OSHA) halves the safe exposure time. This page uses the NIOSH 3 dB rule, which is the more protective of the two and the one hearing scientists prefer.
A dose of 100% means you have used the whole day’s allowance. Going over it does not cause immediate injury, and staying under it does not guarantee you are fine forever, but over years the dose is what predicts the damage.
NIOSH Permissible Exposure Time Formula:
Safe Duration (hours) = 8 / 2^((dB − 85) / 3)
Where 85 dB is the NIOSH action level for an 8-hour day.
Safe Exposure Reference (NIOSH standard):
| Sound Level (dBA) | Safe Exposure Time |
|---|---|
| 75 dB | 80 hours (below the floor, not counted) |
| 80 dB | 25 hours |
| 85 dB | 8 hours |
| 88 dB | 4 hours |
| 91 dB | 2 hours |
| 94 dB | 1 hour |
| 97 dB | 30 minutes |
| 100 dB | 15 minutes |
| 110 dB | 1.5 minutes |
| 120 dB+ | Seconds, and immediate damage risk |
The 80 dB floor: NIOSH does not count exposure below 80 dBA toward a daily dose at all, which is why the 75 dB row is marked that way even though the formula still produces a number for it. 80 dB itself is on the floor and does count. Above 80 dB the dose accumulates, and it is a daily budget shared across everything you do that day. A loud commute and a loud evening draw on the same 100%.
Worked Example: Concert venue at 105 dB:
- Safe time = 8 / 2^((105−85)/3) = 8 / 2^6.67 = 8 / 101.6 = 4.7 minutes
Real-World Sound Levels:
- Conversation: 60–65 dB
- Heavy traffic: 85 dB
- Lawn mower: 90 dB
- Rock concert: 100–120 dB
- Gunshot: 140–165 dB
Protection Options: The number printed on the box is a laboratory figure measured on a perfectly fitted plug, and almost nobody fits them perfectly. NIOSH halves the rating for foam plugs and takes a quarter off for muffs. Real-world figures:
- Foam earplugs: about 12 dB, against a labelled NRR of 25 to 33
- Earmuffs: about 17 dB, against a labelled 25 to 30
- Both together: about 23 dB, not the sum of the two
- Custom musician plugs: 9 to 25 dB with a flat response, so music still sounds like music
Twelve decibels does not sound like much next to 32. It is worth 16 times more exposure time, because of the same 3 dB doubling that makes the safe times collapse in the first place.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.