National Institute of Justice Ratings for Body Armor
NIJ Standard 0101.03, 0101.04

While no body armor can offer 100% protection in all circumstances, an adequate level of body armor will protect the wearer from the majority of pistol rounds, and can provide a significantly improved level of safety. The NIJ has developed standards to help you choose the best armor for your agency’s and your personal needs.

The chart below summarizes the standards used to certify body armor performance against varying levels of threats. It can serve as a basic guide to help you determine the level you need. While considering your requirements, keep in mind that the National Institute strongly recommends the selection of armor that will protect against common street threats in your area, and at minimum, from the officer’s own handgun.

Consider this brief excerpt from the National Institute of Justice’s Publication, Selection and Application Guide to Personal Body Armor:

	The first step in selecting the appropriate protection level of body armor is to establish the level of protection 
	that users need based on the realistic weapon threat they face. To date, body armor has not been known to 
	fail to prevent the penetration of a bullet constituting a threat equal to or less than the protection rating of the 
	armor. However, officers have died from wounds received from weapons or ammunition exceeding the rated 
	protection of the armor. While 100-percent protection in all circumstances is impossible, the routine use of 
	appropriate body armor significantly reduces the likelihood of fatal injury. Body armor selection is to some 
	extent a tradeoff between ballistic protection and wear-ability. The weight and bulk of body armor are generally 
	proportional to the level of ballistic protection it provides; therefore, comfort decreases as the protection level 
	increases. All departments should strive to select body armor that their officers will wear, consistent with their 
	ballistic protection requirements. Agencies should ensure that each officer knows and understands the 
	protection that it affords, as well as its limitations.
	The weapons and ammunition commonly found on the street may vary significantly with geographic location. 
	Therefore, information concerning weapons and ammunition that are confiscated in both the local jurisdiction 
	and nearby surrounding areas must be considered, as well as statistics concerning gun sales by local firearms 
	dealers. Such data will permit an assessment of the current threat  from street weapons. The National Institute
	of Justice (NIJ) strongly recommends the selection of armor that protects against both the street threat and the
	officer's handgun. A review of reports on officers killed during the period from 1980 to 2000 shows that 163 of 
	the 1,058 officers killed with a handgun, or on average one in six officers, was killed with his or her own service weapon.
     
The full NIJ Report, with a wealth of valuable information, is available as a pdf.

Body Armor Ratings
NIJ Standard 0101.03, 0101.04

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NIJ LEVEL I:

This armor protects against .22 caliber Long Rifle Lead Round Nose (LR LRN) bullets with nominal masses of 2.6 g (40 gr) impacting at a minimum velocity of 320 m/s (1050 ft/s) or less and 380 ACP Full Metal Jacketed Round Nose (FMJ RN) bullets with nominal masses of 6.2 g (95 gr) impacting at a minimum velocity of 312 m/s (1025 ft/s) or less.

NIJ LEVEL IIA:

(Lower Velocity 9mm, .40 S&W). This armor protects against 9mm Full Metal Jacketed Round Nose (FMJ RN) bullets with nominal masses of 8.0 g (124 gr) impacting at a minimum velocity of 332 m/s (1090 ft/s) or less and .40 S&W caliber Full Metal Jacketed (FMJ) bullets with nominal masses of 11.7 g (180 gr) impacting at a minimum velocity of 312 m/s (1025 ft/s) or less. It also provides protection against Level I threats. Level IIA body armor is well suited for full-time use by police departments, particularly those seeking protection for their officers from lower velocity .40 S&W and 9mm ammunition.

NIJ LEVEL II:

(Higher Velocity 9mm, .357 Magnum). This armor protects against .357 Magnum jacketed soft-point bullets with nominal masses of 10.2 g (158 gr.) impacting at a velocity of 425 m/s (1,395 ft/s) or less and against 9mm full-jacketed bullets with nominal velocities of 358 m/s (1,175 ft/s). It also protects against most other factory loads in caliber .357 Magnum and 9mm as well as the Level I and IIA threats. Level II body armor is heavier and more bulky than either Levels I or IIA. It is worn full time by officers seeking protection against higher velocity .357 Magnum and 9mm ammunition.

NIJ LEVEL IIIA:

(.44 Magnum; Submachine Gun 9mm). This armor protects against .44 Magnum, Semi Jacketed Hollow Point (SJHP) bullets with nominal masses of 15.55 g (240 gr.) impacting at a velocity of 426 m/s (1,400 ft/s) or less and against 9mm full-metal jacketed bullets with nominal masses of 8.0 g (124 gr.) impacting at a velocity of 426 m/s (1,400 ft/s) or less. It also provides protection against most handgun threats as well as the Level I, IIA, and II threats. Level IIIA body armor provides the highest level of protection currently available from concealable body armor and is generally suitable for routine wear in many situations. However, departments located in hot, humid climates may need to evaluate the use of Level IIIA armor carefully.

NIJ LEVEL III:

(High-powered rifle). This armor, normally of hard or semirigid construction, protects against 7.62mm full-metal jacketed bullets (US military designation M80) with nominal masses of 9.7 g (150 gr.) impacting at a velocity of 838 m/s (2,750 ft/s) or less. It also provides protection against threats such as 223 Remington (5.56mm FMJ), 30 Carbine FMJ, and 12-gauge rifled slug, as well as Level I through IIIA threats. Level III body armor is clearly intended only for tactical situations when the threat warrants such protection, such as barricade confrontations involving sporting rifles.

NIJ LEVEL IV:

(Armor-piercing rifle). This armor protects against .30–06 caliber armor-piercing bullets (US military designation APM2) with nominal masses of 10.8 g (166 gr.) impacting at a velocity of 868 m/s (2,850 ft/s) or less. It also provides at least single-hit protection against the Level I through III threats.

Level IV body armor provides the highest level of protection currently available. Because this armor is intended to resist “armor piercing” bullets, it often uses ceramic materials. Such materials are brittle in nature and may provide only single-shot protection since the ceramic tends to break up when struck. As with Level III armor, Level IV armor is clearly intended only for tactical situations when the threat warrants such protection.