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How loud is a library?

40–44dBroom ambient level

A quiet library is about 40 dB. Purdue University's noise comparison chart lists 'library, bird calls (44 dB)' in its 40 dB row and describes 40 dB as the lowest limit of urban ambient sound.

Level
40–44 dBunweighted sound level
Daily limit
No daily limitNIOSH, at the loud end

What the numbers mean

How it was measured. Background level in a library, from Purdue University's noise comparison chart (compiled from Temple University, the Federal Interagency Committee on Noise and a City of Los Angeles study). Weighting not stated.

Purdue's chart places a library in the same row as bird calls at 44 dB and calls 40 dB the lowest limit of urban ambient sound, meaning that towns rarely get quieter than this.

On the same chart, a quiet rural area is 30 dB and a quiet suburb is 50 dB. CDC lists a refrigerator hum at 40 dB, which gives a sense of how quiet a library is: about the level of a fridge in a silent kitchen.

Is it safe?

Below 85 dBA, the level NIOSH allows for a full 8-hour day. (This figure is not A-weighted; treat it as a rough guide.) At this level, sound is not a hearing risk however long it lasts, though it can still disturb sleep or concentration.

Protecting your hearing

No protection needed. A library is a good benchmark: if you cannot hear normal conversation clearly in a room this quiet, it is worth having your hearing checked.

Earplug and earmuff ratings (NRR in the US, SNR in the UK and EU) are lab figures; real-world protection is usually lower. How to read the ratings.

Compared with sounds nearby

Using midpoints of each range. Energy multiplies by 10 every 10 dB; perceived loudness roughly doubles (why).

  • Whisper (20–30 dB): this has about 50× its sound energy and sounds about 3.2× as loud.
  • Quiet rural area (30 dB): this has about 16× its sound energy and sounds about 2.3× as loud.
  • Ocean waves (60–78 dB): it has about 501× the sound energy of this and sounds about 6.5× as loud.
  • Smoke alarm (85 dB): it has about 19,953× the sound energy of this and sounds about 19.7× as loud.

Questions

How many decibels is a library?

About 40 dB according to Purdue University's noise comparison chart.

Is a library quieter than the countryside?

Not usually. Purdue's chart puts a library at 40 dB and a quiet rural area at 30 dB.

Sources

  1. Noise Comparisons (Noise Sources and Their Effects), Purdue University Department of Chemistry, Chemical Safety. Supports: dB_low: 40 dB; dB_high: 44 dB.Library, bird calls (44 dB); lowest limit of urban ambient sound 40Checked 2026-11-02.
  2. Noise Comparisons (Noise Sources and Their Effects), Purdue University Department of Chemistry, Chemical Safety. Supports: body/faq: rural comparison.Quiet rural area 30Checked 2026-11-02.
  3. Noise Comparisons (Noise Sources and Their Effects), Purdue University Department of Chemistry, Chemical Safety. Supports: body: quiet suburb row (50 dB).Quiet suburb, conversation at home. Large electrical transformers at 100 ft 50Checked 2026-11-02.
  4. What Noises Cause Hearing Loss? (archived copy, 31 Dec 2022), CDC National Center for Environmental Health. Supports: body: refrigerator comparison.Refrigerator hum 40Checked 2026-11-02.

This page is general information, not medical advice. If you have ringing in your ears, muffled hearing or any change in your hearing, see an audiologist or your doctor.