How loud is a gunshot? Decibels by firearm, from the published measurements

A gunshot is loud enough that a single one can matter. The honest answer to "how loud" is a range, not a number, because it depends on the firearm, the ammunition, where the microphone sits and whether you're indoors. Below you'll find the published measurements from federal hearing researchers and professional bodies, each with its source and how it was measured, so you can see where the popular figures come from.

We don't measure gunfire ourselves, and we don't fill gaps with estimates. If no source we could check gives a number for your exact caliber, we say so.

Gunshot decibels by firearm type

The most detailed breakdown for recreational shooters comes from a 2017 review by Meinke, Finan, Flamme, Murphy (NIOSH) and colleagues in Seminars in Hearing, hosted by the CDC (Meinke et al., 2017). Their Table 1 lists the range of mean unweighted peak sound pressure levels for recreational firearms, measured at the left ear of a right-handed shooter (the ear ASHA says typically takes more hearing loss when right-handed shooters fire rifles and shotguns):

The same review sums it up: "Peak sound pressure levels (SPLs) from firearms range from [about] 140 to 175 dB. The majority of recreational firearms (excluding smallcaliber 0.17 and 0.22 rifles and air rifles) generate between 150 and 165 dB peak SPLs."

What other published measurements say

Other official sources land in the same territory, each measuring something slightly different. That's why you see different "gunshot decibel" figures quoted online.

Notice that ASHA's simplified guidance puts shotguns and pistols "up to 140", while the NIOSH measurements put them well above that. We report both as published. For deciding whether you need hearing protection, the disagreement doesn't matter: every source above says you do.

How loud is a 9mm, a .22 or a 5.56?

This is the question most people type, and the straight answer is that none of the sources we could verify publishes a single decibel figure for one caliber that you could apply to your gun. Here's what they do publish:

• 9mm: NIOSH measured Colt 9-mm pistols as part of a group of law-enforcement firearms whose peak levels ranged from 155 to 168 dB SPL (NIOSH 2009-136). NIOSH's per-gun results appear only in a chart, so we can't pull out a 9mm-only number. More broadly, Meinke et al. put pistols larger than .22 caliber at about 148 to 171 dB.
• .22 LR: Meinke et al. list .22 caliber pistols at about 155 to 158 dB and .17 and .22 caliber rifles at about 140 to 144 dB. Murphy and colleagues cite 144 dB SPL for a .22 caliber rifle. Even the quietest of these is at or above the 140 dB limit described below.
• 5.56 / .223: NIOSH's law-enforcement group, measured at 155 to 168 dB SPL, included .223-caliber rifles (NIOSH 2009-136). Meinke et al. put rifles larger than .22 caliber at about 159 to 174 dB.
• 12-gauge shotgun: the NIOSH group above included a 12-gauge, and Meinke et al. put shotguns at about 152 to 170 dB.

If a website gives you one exact number for "a 9mm", ask where it came from and how it was measured.

Why the numbers differ

A handful of things move the measured level, and the sources are open about them:

• Where the microphone is. Meinke et al. measured at the left ear of a right-handed shooter. ASHA notes that "when shooting rifles and shotguns, right-handed shooters typically suffer more hearing loss in the left ear."
• Barrel length. Meinke et al. note that shorter barrels, including those on youth firearms, increase the sound pressure level measured at the shooter's left ear.
• What's around you. Walls, a ceiling, a shooting bench or a table all change the result. More on that below.
• Which "decibel". Gunshot figures are peak levels (dB SPL peak or dBP), the highest instantaneous pressure. Everyday noise figures are usually A-weighted averages (dBA). The two aren't directly comparable, which matters for the comparison table below.

The 140 dB line

The key threshold for impulse noise, sudden bangs like gunfire, is 140 dB peak. OSHA's noise standard states: "Exposure to impulsive or impact noise should not exceed 140 dB peak sound pressure level" ( 29 CFR 1910.95). OSHA's technical manual names "the shooting of a firearm" as an example of impulsive noise (OSHA Technical Manual, Section III Chapter 5).

NIOSH explains what that limit means in practice: "exposure to one event at 140 dB SPL would constitute 100% of a person's daily allowable noise exposure" (Murphy, Byrne and Franks, 2007). ASHA goes further for shooters: "exposure to noise greater than 140 dBP can permanently damage hearing, even from a single occurrence," and people who don't wear hearing protection properly "can suffer hearing loss or ringing in their ears (known as tinnitus) with as little as one shot."

Put the table next to that line and the conclusion is plain. Meinke et al. write that "hearing protection should be used for all types of recreational firearms," and that "reliance upon subjective judgments of auditory risk should be discouraged." In other words, a gun that doesn't sound that loud to you is still loud enough to count.

Compared with everyday sounds

For a sense of scale, here are figures the National Institute on Deafness and Other Communication Disorders publishes (NIDCD, Noise-Induced Hearing Loss). They're A-weighted averages, not peak levels, so treat this as a rough guide rather than a like-for-like comparison.

NIDCD adds that long or repeated exposure to sounds at or above 85 dBA can cause hearing loss, and that "extremely loud bursts of sound, such as gunshots or explosions" can cause hearing loss that is "immediate and permanent." NIDCD also lists target shooting and hunting among the recreational activities that put you at risk.

Indoor vs outdoor

None of our sources gives a single "indoor adds X dB" figure, so we won't invent one. What they do say is consistent. Meinke et al.: "Shooting in an enclosed, reflective, reverberant environment (indoors or hunting blind) increases the hazard to hearing," and "shooting from a bench or over a table also increases the peak SPL reaching the shooter's ear." NIOSH researchers add that "in an indoor firing range, reflected sound (reverberation) also becomes an important factor" (Murphy, Byrne and Franks, 2007).

That's why the advice changes indoors. ASHA tells recreational shooters: "If you plan to shoot at an indoor facility, choose one that has been acoustically treated for reverberation (i.e., sound bouncing off the walls) and wear double hearing protection." NIOSH recommends earplugs and earmuffs together at indoor ranges for range workers and people who shoot for their job (NIOSH 2009-136), and the physics doesn't change for a weekend visitor. Our indoor vs outdoor shooting range guide covers what else changes.

What this means for your ear protection

With peak levels far above 140 dB, your hearing protection has a lot of work to do. Here's what to look for:

• A published NRR. The NRR (Noise Reduction Rating, the number on the package) is required by the EPA. Higher is more protection on paper. But the EPA's own label rule says the NRR "may not be an accurate indicator of the protection attainable against impulsive noise such as gunfire" ( 40 CFR 211.204-4), so don't subtract the NRR from a gunshot figure and call the result safe. Our guide to what NRR you need explains the label.
• Two layers when it's loud. In one NIOSH example, a David Clark earmuff reduced a 12-gauge shotgun's peak from 161 dB to 130 dB SPL, and adding "a deeply-inserted foam earplug adds another 21 dB to the attenuation" (Murphy, Byrne and Franks, 2007). Those are measurements of specific products, but they show why doubling up is the standard advice indoors. See double hearing protection.
• A good fit. Foam plugs must be inserted the way the package shows, and muffs must seal against your head. Glasses temples under the cushions can let sound leak in; see ear protection with glasses.
• Electronics if you need to hear. NIOSH suggests electronic muffs over passive earplugs for shooters who need to hear instructions (NIOSH 2009-136).

Specs above come from the MAX-1 listing on Honeywell's licensed store and Howard Leight's Impact Pro page. For the full field, see our best hearing protection for shooting and, for indoor ranges specifically, best ear protection for indoor ranges.