π Noise Exposure Dose Calculator
Safe listening time by the NIOSH standard.
For informational purposes only, not medical advice. Consult a healthcare professional.
Hearing damage depends on dose: loudness times duration. NIOSH sets the recommended exposure limit at 85 dBA for 8 hours, with a 3-dB exchange rate: every 3 dB louder halves the safe time. At 88 dBA you get 4 hours, at 91 about 2, at 100 just 15 minutes. This calculator converts any noise level into safe daily time and your actual dose as a percent of the limit.
Enter the noise level in dBA and your daily exposure hours. The calculator returns the allowed time and your dose percentage. Concerts, power tools, and max-volume earbuds all live in the dose-accumulating range.
How to Use This Calculator
Estimate the dBA: phone sound-meter apps are roughly accurate for steady noise. Enter the level and your daily hours at it. Read the safe time and dose. If the dose exceeds 100%, cut time, lower volume, or wear protection: foam plugs properly inserted cut about 15-25 dB in practice.
Estimate or measure the noise level in dBA.
Enter the level and daily exposure hours.
Read the safe time and your dose percent.
Reduce time, volume, or add hearing protection to get under 100%.
The 3-dB Exchange Rate
Dose % = 100 x actual hours / safe hours
Decibels are logarithmic: +3 dB doubles sound energy, so NIOSH halves allowed time for each 3 dB to keep energy dose constant. The formula anchors at 85 dBA for 8 hours, the limit NIOSH recommends to prevent material hearing impairment over a working lifetime. OSHA's legal PEL is less protective (90 dBA with a 5-dB exchange), which is why this calculator uses NIOSH: the stricter standard better protects hearing. Dose adds across the day: 2 hours at 91 dBA (100% dose) plus 4 hours at 88 dBA (100%) is a 200% day.
Worked Example
At 100 dBA for 2 hours daily: safe time is 15 minutes, so the daily dose is 800%, which reads "Daily dose 800% - Over the NIOSH limit: reduce time or use protection". Drop to 94 dBA and safe time quadruples to an hour; the 3-dB exchange rate (3 dB: each +3 dB halves safe time) is why small volume changes matter enormously.
Everyday Noise in Dose Terms
Normal conversation is about 60 dBA: unlimited. City traffic 85: the 8-hour line. Lawn mower 90: about 2.5 hours safe. Concert 105-110: minutes. Earbuds at max reach 100-105 dBA: the 15-minute zone, which is why teens rack up dose fast. Foam earplugs, properly rolled and inserted deep, realistically remove 15+ dB, turning a 100 dBA concert into an 85 dBA evening.
| dBA | Example | Safe time (NIOSH) |
|---|---|---|
| 85 | City traffic | 8 hours |
| 90 | Lawn mower | 2.5 hours |
| 95 | Subway | 47 minutes |
| 100 | Max earbuds | 15 minutes |
| 105 | Concert | 5 minutes |
| 110 | Power tools | 1.5 minutes |
Hearing Loss Is Permanent
Noise-induced hearing loss and tinnitus do not heal: hair cells do not regenerate. Ringing after noise exposure is injury, not harmless. Get a baseline hearing test if you work in noise, and use protection consistently rather than occasionally. For informational purposes only, not medical advice. Consult a healthcare professional.
Related tools: mean arterial pressure and BMI calculator.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
How loud is too loud?
Above 85 dBA for extended periods. Each 3 dB louder halves safe time: 88 dBA allows 4 hours, 100 dBA only 15 minutes.
What is the NIOSH noise limit?
85 dBA averaged over 8 hours, with a 3-dB exchange rate. It is stricter and more protective than OSHA's legal limit.
How loud are earbuds at max volume?
Typically 100-105 dBA, giving roughly 5-15 minutes of safe listening per day at full volume.
Do foam earplugs really work?
Yes, when inserted properly: expect 15-25 dB of real-world reduction. Shallow insertion is the common failure.
Is ringing after a concert bad?
Yes, it is temporary threshold shift: a warning sign of hair cell stress. Repeated episodes accumulate into permanent loss.
What is the 3-dB exchange rate?
The rule that each 3 dB increase doubles sound energy and halves safe exposure time, keeping total energy dose constant.
Can hearing loss from noise be reversed?
No. Damaged hair cells do not regenerate, which is why prevention is the entire strategy.
Are phone sound meter apps accurate?
Roughly, within a few dB for steady noise with the phone's microphone. Good enough for dose estimates, not for legal compliance.
Is 85 dBA really the danger line for hearing?
It is the occupational line for an 8-hour day under NIOSH rules, not a cliff where damage suddenly starts. Risk accumulates from the combination of level and time: 88 dBA is safe for about 4 hours, 91 for 2, and so on. Brief loud bursts (concerts, power tools) can harm even with quiet the rest of the day.
Do phone apps measure noise accurately?
Roughly, within a few decibels when calibrated, which is fine for screening. Phone microphones are not precision instruments: they clip at very high levels, vary between models, and misread low frequencies. For workplace compliance or legal disputes, a calibrated sound level meter is required; for checking whether your commute is too loud, an app is enough.