WHO · NIDCD · NIOSH
Sound level chart
How loud are everyday sounds, and how long is too long? Compare a level of your own, then see what earplugs or earmuffs are likely to take off.
Compare a level
At least as loud as heavy traffic, heard inside a car (85 dB). Quieter than shouted conversation (90 dB). Inside the typical range for a movie theater; motorcycles and dirt bikes.
85 dBA or more: long or repeated exposure can cause hearing loss (NIDCD).
NIOSH daily limit: 8 h. WHO weekly listening: 12 h 36 min.
Hearing protector estimate
| Method | Cut | At the ear |
|---|---|---|
| OSHA, label value: NRR − 7 | 22.0 dB | 78.0 dBA |
| OSHA, field estimate: (NRR − 7) × 50 % | 11.0 dB | 89.0 dBA |
| NIOSH derated (formable (foam) earplugs) | 7.5 dB | 92.5 dBA |
Decibel levels of common sounds
| Sound | Typical level (dB) | NIOSH limit a day | Source |
|---|---|---|---|
| Normal breathing | no limit | WHO | |
| Soft whispering | no limit | WHO | |
| Library | no limit | WHO | |
| Normal conversation | no limit | NIDCD | |
| Movie theater | 5 min 57 s | NIDCD | |
| Doorbell | 25 h 24 min | WHO | |
| Motorcycles and dirt bikes | 1 min 29 s | NIDCD | |
| Heavy traffic, heard inside a car | 8 h | WHO | |
| Shouted conversation | 2 h 31 min | WHO | |
| Headphones at maximum volume, sporting events, concerts | 1 min 29 s | NIDCD | |
| Hand drill | 24 min | NIOSH/CPWR | |
| Hair dryer | 15 min | WHO | |
| Car horn at 5 metres | 4 min 43 s | WHO | |
| Spray painter | 4 min 43 s | NIOSH/CPWR | |
| Shouting in the ear | 1 min 29 s | WHO | |
| Chain saw | 1 min 29 s | NIOSH/CPWR | |
| Sirens | 1 s | NIDCD | |
| Hammer drill | 35 s | NIOSH/CPWR | |
| Pneumatic precision drill | 11 s | NIOSH/CPWR | |
| Jackhammer | under 1 s | WHO | |
| Airplane taking off | none (ceiling) | WHO | |
| Fireworks show | none (ceiling) | NIDCD | |
| Firecrackers | none (ceiling) | WHO |
70 dB or less71 to 84 dB85 dB or moreLevels as each source prints them; NIDCD figures are dBA.
Reading the chart
Each figure is a typical level as published by the source in the last column. Real levels depend on distance and surroundings: a car horn heard from 5 metres is far louder than from across the street, and a hair dryer is loudest right at your ear. Ranges show how much one kind of sound varies. The NIOSH column is the daily time NIOSH recommends at the top of each range, from 8 hours at 85 dBA halving every 3 dB.
Every 10 dB is ten times the sound energy, so the step from 90 to 100 dB is far bigger than from 50 to 60. NIDCD says sounds at or below 70 dBA are unlikely to cause hearing loss, and long or repeated exposure at 85 dBA or above can.
Hearing protection notes
The NRR printed on earplugs and earmuffs comes from a laboratory test with careful fitting, and real-world protection is usually lower. OSHA subtracts 7 dB from the NRR when the noise was measured in dBA, and its technical manual halves what is left for a realistic field estimate. NIOSH instead derates the NRR by 25 % for earmuffs, 50 % for foam plugs and 70 % for other plugs before subtracting 7 dB. For plugs and muffs worn together, OSHA credits only 5 dB more than the better of the two.
Fit matters more than the number: roll foam plugs thin and let them expand deep in the ear canal, and keep glasses arms and hair out of earmuff seals. Protection only works while worn, and taking it off for a few minutes in loud noise uses up much of the day's allowance.
Questions
Why do different charts give different decibels for the same sound?
Distance, the particular machine and how the level was measured all change the figure, and many charts leave them out. A level can be a short peak or an average over minutes, A-weighted or not. Treat any chart as a rough guide and measure the sounds that matter to you.
Is 85 dB loud?
It is about as loud as heavy traffic heard from inside a car. It does not hurt, which is why it is easy to underestimate, but NIDCD warns that long or repeated exposure at 85 dBA or more can cause hearing loss, and NIOSH recommends no more than 8 hours a day at that level.
Which hearing protection should I buy?
The one you will wear properly the whole time you are in the noise. For most loud hobbies and jobs a well-fitted protector with a moderate NRR is enough; too much attenuation can make speech and warning signals hard to hear. For very loud work, ask your employer's safety adviser or an audiologist.
Sources
- World Health Organization, Deafness and hearing loss: Safe listening (questions and answers): examples of sound intensity, in dB.
- National Institute on Deafness and Other Communication Disorders (NIH), Noise-Induced Hearing Loss: average levels in dBA, and the 70 dBA and 85 dBA statements.
- NIOSH and CPWR – The Center for Construction Research and Training, Noise levels by decibels (2015): construction tools, in dB.
- NIOSH, Criteria for a Recommended Standard: Occupational Noise Exposure, Revised Criteria 1998, DHHS (NIOSH) Publication No. 98-126: the 85 dBA, 3 dB exchange-rate limit and the 25 / 50 / 70 % NRR derating.
- OSHA, 29 CFR 1910.95 Appendix B (subtract 7 dB from the NRR for A-weighted levels) and the OSHA Technical Manual, Section III, Chapter 5 (50 % field correction, +5 dB for dual protection).