Noise Pollution Calculator – Maximal Exposure Time

Written by Great Medico

Updated September 25, 2026 •2 min read

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Noise risk depends on both loudness and time. A level that may be acceptable for hours at one intensity can reach a full occupational noise dose much faster when the sound level rises only a few decibels.

What this calculator does

This calculator takes one input—continuous A-weighted noise level in dBA—and estimates the NIOSH-style maximum daily exposure time. It is built around the occupational reference of 85 dBA for 8 hours and a 3 dB exchange rate.

How to use it

Enter the representative noise level for the exposure you want to evaluate. For workplace decisions, use a properly measured time-weighted sound level rather than a casual phone estimate. If the noise changes substantially through the day, a single-level calculator is not enough to calculate the combined dose.

How the calculation works

The formula is exposure time = 8 × 2^((85 − dBA) / 3) hours. Every 3 dB increase halves the allowed time: 85 dBA corresponds to 8 hours, 88 dBA to 4 hours, 91 dBA to 2 hours and 94 dBA to about 1 hour.

Example

At the default 85 dBA, the calculator returns 8 hours and identifies the 3 dB exchange rule. Entering 100 dBA would reduce the NIOSH-style time to about 15 minutes for a 100% daily occupational noise dose.

How to interpret the result

The output is an occupational exposure reference, not a guarantee that hearing damage cannot occur below the limit. NIOSH’s 85 dBA/8-hour recommendation is designed for workplace exposure and assumes quieter periods outside work. Hearing conservation also involves controls, monitoring and correctly selected protection.

Limitations and notes

Impulse noise, mixed noise levels, hearing-protector fit and jurisdiction-specific rules are not captured by one number. OSHA and NIOSH criteria can differ, and environmental/recreational noise is not the same regulatory context. Sudden hearing loss, tinnitus after intense noise or acoustic trauma warrants prompt medical attention.