SoundSenseHow loud is 100 decibels?
100 dB is very loud: the level of a loud concert, a sporting event or headphones turned up high, all within the 94–110 dBA range the NIDCD gives for them. At 100 dBA your hearing is at risk within minutes: NIOSH recommends no more than 15 minutes a day, and the WHO's safe listening allowance is 20 minutes a week.
How long is 100 dB safe?
| Guideline | Safe time at 100 dB |
|---|---|
| NIOSH (recommended limit) | 15 minutes a day |
| WHO safe listening | 20 minutes a week |
| OSHA (US workplace law) | 2 hours a day (a less protective, older rule) |
| EU Directive 2003/10/EC | Above the 87 dB(A) limit unless hearing protection brings it down |
OSHA's figure is higher because it uses a 5 dB exchange rate, while NIOSH, the WHO allowances and the EU directive all work on 3 dB. For your own hearing, the NIOSH and WHO figures are the ones to follow.
What is around 100 dB
| Level | Example | Source |
|---|---|---|
| 94–110 dBA | Headphones at full volume, sporting events, concerts | NIDCD |
| 74–104 dBA | Movie theatre, at its loudest | NIDCD |
| 80–110 dBA | Motorcycles and dirt bikes | NIDCD |
| 100 dB | Hair dryer | WHO |
| 105 dB | Car horn at 5 metres | WHO |
100 dB carries ten times the sound energy of 90 dB (a shouted conversation) and a hundred times that of 80 dB (a doorbell).
What 100 dB does to your ears
After a short time at this level many people notice ringing (tinnitus) or muffled hearing. Both can fade within a day, but they are signs of strain on the inner ear, and repeated exposure can make the damage permanent. Noise-induced hearing loss cannot be reversed, which is why the safe times are so short.
How to stay safe at 100 dB
- Wear earplugs at concerts, matches and clubs. Even simple foam earplugs bring the level at your ear down a long way.
- Step back. Outdoors, doubling your distance from the speakers lowers the level by about 6 dB, and every 3 dB less doubles your safe time.
- Take breaks in a quieter area.
- Turn headphones down to a level where you can still hear someone speaking next to you.
Check the level yourself
A sound meter app shows whether a venue is closer to 90 or to 100 dB. Measure for at least 30 seconds where you stand and read the average. SoundSense warns you when the microphone is overloaded or the reading is outside its tested range, which can happen at very loud levels with a phone's built-in microphone; readings are estimates.
A phone cannot measure your headphones this way: its microphone hears the room, not the sound inside your ear. For headphones, use the headphone level or volume limit setting your phone offers, and keep the volume where you can still hear someone next to you.
Sources
- NIDCD, Noise-induced hearing loss, updated 16 April 2025
- WHO, Deafness and hearing loss: safe listening
- NIOSH, Understanding noise exposure limits
- OSHA, 29 CFR 1910.95 Occupational noise exposure
- EU, Directive 2003/10/EC on noise at work
Updated by the SoundSense team at Just IT.