Index Room & AcousticsSafe Listening Time

Safe Listening Time

Daily noise dose from listening level and duration.

Daily limit, NIOSH1 h 35 min

Your daily dose94.5%

Weekly allowance, WHO2 h 30 min

Daily limit, OSHA6 h 4 min

Dose for the day

comfortable

near the limit

over the limit

Permitted time against level

NIOSH limit
OSHA limit
Your listening

The vertical axis is logarithmic. Each 3 dB step halves the time allowed under NIOSH.

Input

Average listening leveldBA

A quiet room is about 40, conversation 60, a loud bar 95, a rock concert 105 to 110.

Listening time per dayh

How it works

Equal energy

Hearing damage from noise depends on the total acoustic energy received. Three decibels more is twice the power, so it does the same harm in half the time. The US National Institute for Occupational Safety and Health recommends at most 85 dBA for eight hours and halves the time for every 3 dB above that:

T = \frac{8\ \mathrm{h}}{2^{(L - 85)/3}}

Dose

Dose is the fraction of the permitted time you have used. Periods at different levels add:

D = 100\,\% \times \sum_i \frac{t_i}{T_i}

Staying under 100% over a working lifetime is expected to protect most people. Under 50% leaves a sensible margin.

Other standards

OSHA, the US legal limit, starts at 90 dBA for eight hours and halves the time every 5 dB. It is much more lenient and is not regarded as protective.
WHO guidance for personal audio allows 80 dBA for 40 hours a week, with the same 3 dB rule.

T_{OSHA} = \frac{8\ \mathrm{h}}{2^{(L - 90)/5}}

T_{WHO} = \frac{40\ \mathrm{h/week}}{2^{(L - 80)/3}}

Using it honestly

Levels here are A-weighted averages, not peaks. Phone sound-level apps are rough guides at best, and headphone levels cannot be measured with a phone at all. If your ears ring or sounds seem dull after listening, the dose was too high regardless of what any calculator says.