How loud is too loud?
By Jonny Rowse. Published .
Two things decide whether a sound damages your hearing: how loud it is, and how long you are exposed to it. A quiet office all day is fine. A drill for ten minutes is fine. A concert for three hours is not.
What the numbers mean
Decibels are not a straight line. The scale is logarithmic, so every three decibels is roughly double the sound energy, even though it only sounds a little louder. That is why small differences at the top of the scale matter so much.
| Level | Sounds like |
|---|---|
| 60dB | Normal conversation |
| 85dB | Heavy traffic, a busy restaurant |
| 100dB | Drums, a petrol lawnmower |
| 105dB | Wind noise inside a motorcycle helmet |
| 120dB | Factory machinery, a chainsaw |
| 130dB | Amplified music at a festival or club |
| 140dB | A gunshot |
The 85dB line is where UK law steps in. Under the Control of Noise at Work Regulations 2005, hearing protection must be provided and worn at a daily average of 85dB, and must be made available from 80dB.
How long you can listen
As the level rises, the safe time falls fast. For each three decibels above 85dB, the time you can be exposed halves:
| Level | Time before the daily limit is reached |
|---|---|
| 85dB | 8 hours |
| 88dB | 4 hours |
| 91dB | 2 hours |
| 94dB | 1 hour |
| 97dB | 30 minutes |
| 100dB | 15 minutes |
| 103dB | About 7 minutes |
A gig at 110dB passes a full working day’s dose in under two minutes. The Health and Safety Executive’s noise exposure calculator (opens in a new tab) works the same sums for a shift made up of different tasks.
The exception: sudden noise
The table above is about exposure that builds up. A single very loud sound, such as a gunshot at 140dB, can damage hearing instantly, with no build up at all. That is why shooting and fireworks need protection even for one shot.
What to do about it
You cannot turn down a festival or a factory, so the practical answer is to lower what reaches your ears. Filtered ear plugs do that without cutting you off from speech, which matters because protection you take out to talk is protection you are not wearing.
Three habits help:
- Put protection in before the noise starts, not once it is uncomfortable.
- Keep it in for the whole time, including breaks in a noisy room.
- Give your ears quiet time afterwards, so the day’s total stays lower.
Questions people ask
- Is 85dB safe?
- For a normal working day, 85dB is the level at which UK law requires hearing protection to be worn. Below it the risk is lower, but it is not zero over many years.
- Why does three decibels matter so much?
- Decibels are a logarithmic scale, so three more decibels is roughly twice the sound energy. That is why the safe listening time halves every time the level rises by three.
- Does using ear plugs mean I can stay longer?
- Yes. Hearing protection lowers the level reaching your ears, which lengthens the time before damage becomes likely, as long as the plugs stay in the whole time.