DecibelwerkQuick answer: Sound starts to damage hearing at around 85 dBA if you’re exposed for hours. NIOSH recommends no more than 85 dBA averaged over 8 hours, and every 3 dB louder halves the safe time: 1 hour at 94 dBA, 15 minutes at 100, under 2 minutes at 110. A daily average of 70 dBA or lower is considered safe for most people.
Why it’s about time as well as loudness
Hearing damage comes from the total sound energy reaching your inner ear. The decibel scale is logarithmic: every 3 dB is double the energy. So 88 dB for 4 hours delivers the same dose as 85 dB for 8 hours. That’s why a short, loud concert can do as much harm as a long shift in a moderately noisy workshop.
The two numbers you’ll see quoted come from two US agencies:
- NIOSH (the research agency): 85 dBA for 8 hours, with a 3 dB exchange rate. This is the protective limit and the one to use for your own ears.
- OSHA (the workplace regulator): 90 dBA for 8 hours with a 5 dB exchange rate. That’s the legal limit for employers, and it’s more lenient. Employers must start a hearing conservation program from an 85 dBA 8-hour average.
Safe time at each level
| Level (dBA) | NIOSH safe time per day | OSHA legal limit per day | Sounds like |
|---|---|---|---|
| 85 | 8 hours | over 8 hours | A busy street |
| 88 | 4 hours | over 8 hours | |
| 91 | 2 hours | about 7 hours | An underground train station |
| 94 | 1 hour | about 4.5 hours | A lawn mower |
| 97 | 30 minutes | 3 hours | A hand drill |
| 100 | 15 minutes | 2 hours | Earbuds at full volume |
| 105 | about 5 minutes | 1 hour | A motorcycle |
| 110 | under 2 minutes | 30 minutes | A concert, a car horn, a nightclub |
Typical sources come from the US military’s Hearing Center of Excellence and the American Academy of Audiology; they’re approximate and change a lot with distance. The NIDCD puts it in plain terms: damage can start after a few hours at 85 dBA, around 14 minutes at 100 dBA, and about 2 minutes at 110 dBA.
How to tell how loud it is where you are
You can’t judge decibels by ear. A common rule of thumb: if you have to raise your voice to talk to someone an arm’s length away, it’s probably above 85 dB.
For a number, measure it:
- Apple Watch: the Noise app samples the A-weighted level and can warn you when the 3-minute average passes a threshold you choose.
- iPhone: the free NIOSH Sound Level Meter app, or a meter app like Decibelwerk. Both read the microphone in a mode that doesn’t boost quiet sounds.
- Hold the phone at ear height, case off, for at least a minute, and read the average (Leq) rather than the needle’s peaks.
You can also turn any reading into a safe time with the free noise exposure calculator.
What to do when it’s too loud
- Move away. Outdoors, doubling your distance from the source cuts about 6 dB, which quadruples your safe time.
- Take breaks. Ten minutes somewhere quiet gives your ears a rest and lowers your daily average.
- Wear protection. Foam earplugs, musician’s earplugs or earmuffs lower the level reaching your ear. The NIDCD recommends protection at 85 dBA and above.
- Turn it down. On headphones, the iPhone can cap volume in Settings › Sounds & Haptics › Headphone Safety.
Ringing, muffled hearing or a feeling of fullness after noise are warning signs. If they last more than a day, see a doctor or audiologist.
For everyday levels side by side, see the decibel chart of common sounds.