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How loud is 100 decibels?

100 dB is a hand drill, headphones at maximum volume or a train passing under a bridge. NIOSH recommends no more than 15 minutes a day. Many people regularly exceed this with earbuds without realising it.

100dB

Extremely loud

Hearing damage possible within minutes. Protect your ears.

050100150

Sounds around 100 dB

  • Motorcycle passing95 dB
  • Under a railway bridge as a train passes100 dB
  • Headphones at max volume100 dB
  • Power drill100 dB
  • Jackhammer105 dB

Is 100 dB safe?

NIOSH recommends a maximum of 15 min per day at 100 dB(A). The more lenient US OSHA workplace limit is 2 hr.

NIOSH
15 min
OSHA
2 hr

Where you hear 100 dB

100 dB is a hand drill, a motorcycle at full throttle, a train crossing a steel bridge or headphones at or near maximum volume on many devices. The WHO-ITU safe listening standard is built on a weekly sound allowance equal to 80 dB for 40 hours; at 100 dB that allowance is used up in about 24 minutes.

Practical tips at 100 dB

Keep exposure at 100 dB short. For headphones, a simple test is whether you can still hear someone speaking at arm’s length; if not, you are probably well above 85 dB. Most phones offer a volume limit and headphone level warnings in their settings, and both are worth switching on.

The physics of 100 dB

Sound pressure
2 Pa
Sound intensity
0.01 W/m²
Energy vs. threshold of hearing
10¹⁰×

How does 100 dB compare?

80 dB

100 dB sounds about 4× as loud as 80 dB, with 100× the sound energy.

90 dB

100 dB sounds about 2× as loud as 90 dB, with 10× the sound energy.

110 dB

100 dB sounds about 2× quieter than 110 dB.

120 dB

100 dB sounds about 4× quieter than 120 dB.

Measure 100 dB yourself

Open the free sound meter, press Start and see whether your environment is above or below 100 dB.

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Frequently asked questions

Is 100 dB safe?

NIOSH recommends a maximum of 15 min per day at 100 dB(A). The more lenient US OSHA workplace limit is 2 hr.

Sounds around 100 dB

Motorcycle passing (95 dB), Under a railway bridge as a train passes (100 dB), Headphones at max volume (100 dB), Power drill (100 dB), Jackhammer (105 dB)

How does 100 dB compare?

100 dB sounds about 4× as loud as 80 dB, with 100× the sound energy. 100 dB sounds about 2× as loud as 90 dB, with 10× the sound energy. 100 dB sounds about 2× quieter than 110 dB. 100 dB sounds about 4× quieter than 120 dB.

Sources

Exposure limits follow the NIOSH REL (85 dB(A), 3 dB exchange rate) and the OSHA PEL (90 dB(A), 5 dB exchange rate). Example levels are typical values; real sources vary with distance and conditions.

  1. Noise and hearing loss basics (NIOSH recommended exposure limit), CDC / NIOSH
  2. 29 CFR 1910.95: Occupational noise exposure, US OSHA
  3. Environmental Noise Guidelines for the European Region (2018), World Health Organization
  4. Safe listening devices and systems: a WHO-ITU standard (H.870), World Health Organization
  5. Noise-Induced Hearing Loss, NIH / NIDCD

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