Noise exposure dose calculator
Hearing damage depends on both level and time. Every few decibels halves the time you can safely spend at it.
dBA
hours
dBA
Safe exposure time
0.794hours
- In minutes
- 47.6
- Dose from your exposure
- 252.0 %
- Within the daily limit
- 0
- Time left at this level
- 0.000
- Equivalent eight-hour level
- 89.00 dBA
- Level that would be safe for your duration
- 91.00 dBA
Show the working
- Sound level = 95
- Exposure time = 2
- Exchange rate = 3
- Criterion level = 85
- Safe exposure time = 8 / 2^((95 - 85)/3) = 0.793 701
- Dose from your exposure = 0.793 701 > 0 ? 2 / 0.793 701 * 100 : 0 = 251.984
- Within the daily limit = 251.984 <= 100 ? 1 : 0 = 0
- Time left at this level = max(0.793 701 - 2, 0) = 0
- Equivalent eight-hour level = 85 + 3 * log2(2/8 * 2^((95 - 85)/3)) = 89
- In minutes = 0.793 701 * 60 = 47.622
- Level that would be safe for your duration = 85 + 3 * log2(8/2) = 91
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- allowed time = 8 hours / 2^((level - criterion) / exchange rate)
- a 3 dB exchange rate halves the allowed time for every 3 dB, which matches the physics of energy
The 3 dB exchange rate is the one that follows from equal energy. The 5 dB US rule is a historical compromise and is more permissive.
Hearing damage from noise is cumulative and permanent. There is no recovery from the loss, only prevention.