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How Loud Is 40 Decibels (dB)? With Noise Comparison Chart

decibel meter

How loud is 40 decibels (dB)? To put it into perspective, 40 dB is about the noise level of a quiet library. In other words, it’s pretty quiet. But how does that compare to other everyday sounds?

To give you an idea, we’ve put together this article to give you an idea of how loud 40 dB would sound. Let’s get into it!

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What Is a Decibel (dB)?

The decibel, or dB, is the unit of sound measurement. The decibel scale is a logarithmic scale. Basically, this means that for every 10 dB you see on the scale, there is a tenfold increase in sound level.

So if something makes a noise at 40 dB, it sounds ten times as loud as something that makes a noise at 30 dB. Conversely, if something makes a noise at 20 dB, it sounds ten times as quiet as something that makes a noise at 30 dB.

man holding sound level meter
Image By: Azja, Shutterstock

What Does Decibel Mean?

The decibel scale is a way of measuring the intensity of sound. The higher the decibel level, the louder the noise. Noise levels are often given in dB(A). This scale dampens or attenuates the effects of very low or high noise levels so that they are more comparable to human hearing. On the dBA scale, the lowest possible noise level is 0 dB.

Check out this noise comparison chart. Take a look and see for yourself how 40 dB stacks up against some common sounds.

Sound Decibel
Jet (100 feet away) 140
Thunder 120
Chain saw 110
Lawn mower 107
Boeing 727 (6,000-foot altitude) 90
Traffic 85
Small auditorium 75 to 85
Landline dial tone 80
Vacuum cleaner 75
Normal conversation 60 to 70
Office building 60 to 65
Refrigerator 55
Bird calls 40
Whisper 25
Breathing 10

Is 40 dB Loud for Sleep?

Now that you know how loud 40 dB is, you may be wondering if it’s too loud for sleep. For most people, 40 dB is too loud, as 30 dB is the prescribed noise level for sleep. However, some people are light sleepers and may even be bothered by noise levels as low as 30 dB.

If you find that 30 dB is too loud for you, consider using a white noise machine to help you sleep. White noise machines generate calming sounds like rainfall or ocean waves that can help to mask disruptive noises and lull you to sleep.

woman sleeping at home
Image By: StockLite, Shutterstock

At What dB Does Hearing Loss Begin?

Most people begin to experience hearing loss when noise reaches 85 dB. That’s about the same volume as city traffic or a vacuum cleaner. Prolonged exposure to noise at this level can cause permanent damage to your hearing.

What dB Causes Physical Pain?

Noise at 120 dB or higher can cause physical pain. That’s about the volume of thunder or a gunshot at close range. It’s loud enough to cause physical pain and damage your hearing over time.

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If you know how loud 40 dB is, it can be helpful to compare it to other sounds. For example, normal conversation is about 60 dB, while a lawn mower is somewhere between 90 and 110 dB. So 40 dB is much quieter than either of those sounds and, therefore, won’t be as likely to damage your hearing.

It’s important to protect your ears from any sound louder than 85 dB, as this can still cause hearing loss over time. Keep these comparisons in mind the next time you’re wondering how loud a particular noise is.

See also:

Featured Image Credit: JRJfin, Shutterstock


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