Free tool
Noise dose calculator
Set how loud and for how long, and see what share of a day’s safe noise it uses. The answer is usually further from intuition than people expect: at 100 dBA — a loud bar — the whole day’s allowance is gone in 15 minutes.
Share of a day’s safe noise
800%
Far past it. At 100 dBA the allowance is 15 minutes, and this is 8× as much. Hearing protection is the difference between this number and a much smaller one.
Why 3 decibels halves the time
Decibels are logarithmic, so an increase of 3 dBA is a doubling of sound energy — and NIOSH’s exchange rate follows that physics directly. Every 3 dBA above 85 halves how long the exposure can last before it reaches the same daily dose.
- 85 dBA8 hours
- 91 dBA2 hours
- 100 dBA15 minutes
- 109 dBA2 minutes
- 115 dBA28 seconds
Which is the whole argument for earplugs at a concert: moving 105 dBA down to 90 does not make the evening 15% safer, it makes it about thirty times longer before the same dose is reached.
Where the numbers come from
One source and three constants. NIOSH sets a threshold of 85 dBA and an exchange rate of 3 dBA, with 100% of the daily dose defined as 85 dBA over eight hours. Everything this calculator does follows arithmetically from those three numbers — there is no adjustment, weighting or judgement added on top.
The preset levels are a different kind of thing, and worth separating. They are commonly cited approximations offered so the slider has meaning, not measurements. Nothing here claims to know how loud your particular venue, workshop or pair of headphones is.
What this is for
Mostly, for seeing what hearing protection actually buys. Earplugs are usually described by how many decibels they remove, which sounds modest — 15 or 20 dB off a concert. Run those numbers through the exchange rate and the same reduction turns a dose you exceed in minutes into one you would need most of a day to reach.
That is the argument made concretely rather than rhetorically, which is the only reason this is a tool. For what to actually wear, see choosing earplugs; for the legal picture at work, workplace hearing rights; and for what noise does to hearing in the first place, noise-induced tinnitus.
Frequently asked questions
How long can I safely listen to something loud?
It depends on how loud, and the relationship is steeper than most people expect. NIOSH sets a full day's dose as 85 dBA for eight hours, with a 3 dBA exchange rate — every 3 decibels above that halves the time. So eight hours at 85 dBA, one hour at 94, and about a quarter of an hour at 100 are all the same dose.
Why does 3 decibels halve the time rather than a bigger number?
Because decibels are logarithmic. An increase of 3 dBA is a doubling of sound energy, so it takes half as long to deliver the same total amount. The exchange rate is not a safety-margin convention; it follows from the physics of what a decibel is.
Is this the same as the OSHA limit?
No, and they differ in ways that matter for a US workplace. This calculator uses the NIOSH recommended criterion. OSHA's enforceable standard uses a different action level, permissible exposure limit and exchange rate, which is covered in the article on workplace hearing rights. If you are asking about your legal position at work rather than your ears, start there.
Where do the sound levels in the presets come from?
They are commonly cited approximate levels for those situations, offered as anchors so the slider means something — not measurements of any specific place. A real level depends on the room, the equipment and where you stand. If you want an actual figure, a sound level meter or a dosimeter is the tool; a website is not.
Does staying under 100% mean my hearing is safe?
It means the exposure is inside a criterion designed to limit hearing loss across a working population over a career. It is not a guarantee for an individual, it says nothing about tinnitus specifically, and susceptibility varies. Treat it as a way to compare exposures and to see what hearing protection buys you, rather than as a licence.
Criterion and exchange rate as stated in Russell & Yamaguchi, Journal of the American Academy of Audiology, 2018: NIOSH standards of 85 dBA threshold and 3 dBA exchange rate, with the 100% daily dose defined as 85 dBA over eight hours.