Body Armor Levels | Ratings Compared

Body Armor Levels | Ratings Compared

Different weapons pose different levels of threats. As such, different body armor products offer different levels of protection. Body armor products are categorized into different levels according to the level of ballistic or knife stab protection they offer.

The US National Institute of Justice (NIJ) has come up with standards to measure protection levels. NIJ also works very closely with the UK Centre for Applied Science and Technology (CAST) to develop globally accepted body armor standards. The two authorities work hand in hand while testing body armor. As such, body armor that has satisfied certain NIJ standards level will have satisfied CAST standards for that level as well.

The protection standards of body armor are outlined by the level of threat against which they can protect you from. For instance, ballistic threat levels are explained in terms of the size and speed of bullets that the body armor in that level can stop. As such, before you purchase body armor, you need to fully understand the level of threat you are facing based on NIJ standards. The same standards are used to ensure military personnel and law enforcement officers are wearing body armor that offers optimal protection while in an operation.

Threats are categorized into three major categories, as far as the manufacture or standardizing of body armor is concerned. They are; ballistic threats, edged blade threats, and spiked weapon threats. Ballistic threats are all the threats that involve gunfire. Edged blade threats include threats posed by cutting and stabbing weapons such as knives and machetes. Spike weapon threats include threats posed by piercing weapons such as arrows, spears, and throwing knives. Below, we explore the various body armor protection levels as per these threat categories.

Ballistic Levels

Ballistic threats are arguably the most faced threat by people in the modern world. Many people looking for body armor are seeking to protect themselves against ballistic threats. NIJ has a very comprehensive body armor ballistic protection level rating system. The levels range from Level IIa to Level IV. Higher levels mean more body armor thickness, weight, and protection.

Basically, more layers of ballistic fiber are added to the body armor to make it more protective with each rise in level. This addition is a delicate process though. Body armor weight is a very crucial factor. Nobody wants to be wearing very heavy body armor, especially for military personnel. It would hinder the maneuverability and speed. For them, one kilogram could be the difference between life and death.

Here is a summary table of the latest NIJ Ballistic Protection Standards.

Bullet Features

Level IIA

Level II

Level IIIA

Level III

Level IV

Bullet Caliber

9 mm Luger

.40 S&W

9 mm Luger

.357 Mag

.357 SIG

.44 Mag

7.62 mm NATO

30.06 M2 AP

Bullet Weight

8.0 g (124 gr)

11.7 g (180 gr)

8.0 g (124 gr)

10.2 g (158 gr)

8.1 g (125 gr)

15.6 g (240 gr)

9.6 g (147 gr)

10.8 g (166 gr)

Bullet Diameter

9 mm (.355 in)

10 mm (.400 in)

9 mm (.355 in)

9.1 mm (.357 in)

9.0 mm (.355 in)

10.9 mm (.429 in)

7.62 mm (.308 in)

7.62 mm (.308 in)

Muzzle Velocity in fps (feet per second)









Armor Thickness







Level IIA

NIJ Level IIA is the most basic body armor protection level. Body armor in this category is tested using a 9mm FMJ (Full Metal Jacket) bullet travelling at a speed of 1225 fps (feet per second). It is further tested by firing a .40 S&W (Smith & Wesson) FMJ bullet travelling at 1155 fps at the armor. Body armor is certified as Level IIA complaint if it can stop these bullets, which, going by the speed, are obviously fired from small and lightweight handguns.

Keep in mind that body armor standardization is not just about preventing penetration. A bulletproof vest could stop the bullets mentioned above, but still, fail Level IIA certification if it cannot reduce the blunt trauma caused by the bullets. In fact, level IIA could stop the bullets used in testing level II body armor from penetrating, but the blunt trauma would still be dangerously high.


Level IIA body armor is very lightweight. It consists of a few thin layers of aramid fibers or any other ballistic fibers. Most of the body armor products in this level weigh less than 10 pounds. Level IIA body armor is commonly used by civilians and law enforcement officers who are seeking protection against low impact bullet fire. Level IIA body armor is also preferred because it is easy to conceal and comfortable to wear. Bulletproof vests in level IIA have a maximum thickness of 4mm.  If any of the bullet fire mentioned above hits you while wearing effective level IIA body armor, the worst you could suffer is a bit of blunt trauma, that is unlikely to cause an injury.

As a result of the uncertainties in the kind of weapons, people are using on the streets or anywhere else, Level IIA body armor is slowly falling out of favor. Many people are skeptical about it, and would not want to take chances. Level IIA body armor products are mainly special order items nowadays. That does not imply that there’s any difficulty in obtaining them. 

Level II

Level II body armor is slightly thicker and heavier than Level IIA body armor. It can stop and absorb trauma from bullets with higher impact. Level II body armor is tested using a 9mm FML RN bullet moving at a speed of 13055 fps. This is the same bullet used for level IIA, but in this case, it is moving faster hence higher impact. The body armor is also tested using a .357 Magnum JSP (Jacketed Soft Point) moving at a speed of 1430 fps. This kind of fire power is still from a handgun, but the handguns used in this case are obviously stronger than those used in level IIA tests.

NIJ level II body armor will stop all the bullets mentioned above, and obviously, all those mentioned in Level IIA. The extra thickness is to ensure the armor can provide ample protection against the trauma from the higher impact bullets. Although level II body armor is heavier than level II body armor, it is still incredibly lightweight, comfortable to wear, and easy to conceal. Body armor in this level cannot protect against rifle bullet fire.


Level II body armor has a maximum thickness of 5mm. Bulletproof vests in this category feature several layers of Kevlar or other aramids. While it can stop some of the bullets used to test level IIIA body armor, the blunt trauma would be too much and could possibly cause an injury.

Level II body armor is commonly used by council workforce officers. The armor provides them with protection against handgun fire, as well as physical assault. It also ensures it does not weigh them down too much. They are able to maneuver and move around without getting fatigued. It is a favorite to many civilians as well. As mentioned earlier, level II body armor is lightweight and easy to conceal. It is also more protective than level IIA body armor.

Level IIIA

Level IIA body armor still provides protection against handgun fire, but it is sturdier than level II body armor. Level IIIA body armor is tested using a .357 SIG FMJ FN (Flat Nose) bullet travelling at a speed of 1470 fps. It is further tested using a .44 Mag SJHP (Semi-Jacketed Hollow Point) bullet, moving at a velocity of 1430 fps. Note that these bullets are heavier and travelling faster than those used in testing level II body armor. Level IIA body armor can also protect against 9mm and .44 Mag. bullets shot by a submachine gun. Level II body armor cannot adequately protect against such gunfire.

Level IIIA body armor delivers the perfect balance between protection level and comfort. It is quite protective against most handgun-shot bullets, and still has a decent level of comfort for the wearer. Although not as light as level II body armor, it cannot be said to be heavy. It is still quite easy to disguise as well. Level II body armor delivers more comfort than Level IIA body armor, but at the expense of losing some level of protection.

Getting hit by a 9mm FMJ bullet travelling at a speed of 1225 fps, similar to the one used to test level IIA body armor, while wearing level IIA bulletproof vest is like getting hit by a small rock. It cannot penetrate, and the trauma is completely subdued. The most you’d suffer is a slight sting. The .357 SIG FMJ FN and .44 Mag SJHP used in the tests would cause more impact and possibly sting more, but they would still be subdued. They are highly unlikely to cause injury. Level IIIA body armor is quite effective in subduing blunt trauma and will allow the user to return fire even after getting hit.


Level IIIA is the highest level of soft body armor. Soft and hard body armor is distinguished by the materials used in their manufacture. Soft body armor is made with soft ballistic materials and it is lightweight and flexible. On the other hand, hard body armor is made of tough rigid materials and it is bulky. The next levels, i.e. level III and level IV consist of hard body armor.

It is important to also keep in mind that bulletproof vests, which are the most common body armor products, are a combination of ballistic plates and plate carries. The vest itself is just a carrier, and it only becomes bulletproof when the ballistic plates are inserted.

A good thing is that you can use one plate carrier with ballistic plates of different levels. That allows you to raise your body armor’s level of protection without necessarily having to purchase another complete bulletproof vest. You must ensure the carrier fits properly, and the ballistic plates fit in the carrier perfectly as well. Anything short of that will still be exposing you to risks. Also, certain carriers are made for specific inserts. You must ensure you have the right combination.

Level III

Level III takes everything to a whole new level. It involves serious gunfire and threats. Level III body armor is designed to protect against rifle gunfire. Level III body armor is tested using a 7.62 mm FMJ steel jacketed bullet travelling at a speed of 2780 fps. Such speed is provided to the bullet by NATO classified rifles. This is some serious gunfire that can drop someone dead in an instant.

Level III body armor must have solid ballistic plates. In some instances, the carrier vest is soft body armor in itself and could rank as Level IIA or Level IIIA. When the appropriate hard armor plates are inserted in the carriers they are retested to ensure they are up to the Level III standard. Such carrier vests are clearly labelled to indicate that they only provide Level III protection when they have the appropriate ballistic plates on.  The most common armor plates are;
  • 6mm/¼’’ ballistic steel plates
  • 13mm/½’’ ceramic plates
  • 25mm/1’’ Polyethylene plates

    The hard ballistic plates significantly increase the weight of Level III body armor as compared to the lower levels. This kind of body armor is also quite difficult to disguise. It is more common with trained officers in tactical forces. They use it when they are facing confrontations that involve serious gunfire. While civilians are free to purchase and use such body armor, it would be too heavy for them. They would find it hard to maneuver around while carrying out ordinary day to day activities. It is, therefore, not very popular among civilians.

    The level III armor plates are metal like. The carrier vests are also quite thick. The bullets and rifles mentioned above are very powerful. In most instances, such gunfire will drop you down when you get hit, even when you have level III body armor on, but will not penetrate. If you were to get hit with the kind of gunfire used to test level IV body armor while wearing level III body armor, it would still not penetrate but the trauma would be too much and dangerous. 

    Level IV

    Level IV is the highest NIJ standard of protection that body armor can provide. Body armor in this level provides the ultimate protection against gunfire. Bulletproof vests in this category also consist of carrier vests and hard ballistic plates. They are tested together as a unit in order to certify them as level IV complaint. Level IV body armor is tested using a 30.06 M2 AP (Armor Piercing) bullet moving at a speed of 2880 fps. This kind of gunfire is obviously shot from an assault rifle and would certainly one with very slim survival chances if they get shot. Level IV body armor can save you from such gunfire. It will stop the bullet and absorb some of the trauma, although the impact will still be a bit high and might throw you backwards. 

    The carrier vest of soft armor on its own, and has to satisfy certain NIJ conditions to be certified as part of Level IV armor. It cannot offer level IV protection on its own though. The inserts have to be on for optimum protection. The carrier vests are clearly labelled to indicate what level of protection they offer, and which inserts are needed for them to be level IV bulletproof vests. A commonly used level IV insert is the 18mm/¾ ‘’ ceramic plate. The other popular level IV plate is the 12mm/½’’ ballistic steel plate, although it is too heavy to be used as body armor. It is mainly used as vehicle armor.

    Level IV armor is bulky. It is also not possible to disguise this kind of armor. It would be difficult for any untrained person to use this body armor. Putting it on is a challenge in itself. Level IV body armor is mainly issued to military officers and other security forces who might go to combat or find themselves in highly confrontational environments. Although there is a lot of uncertainty on the streets today, it is highly unlikely that there are civilians facing ballistic threats that would necessitate them to wear level IV body armor. People like journalists who film in conflict-laden areas might need to use level IV body armor.

    As mentioned earlier, all the body armor in level III and level IV is classified as hard body armor. We’ve already seen that it is heavy and rigid. It is important to mention that, even with all these toughness, no single body armor can be said to be 100% protective. You cannot have the body armor covering every single inch of your body. As such, even while you have body armor on, you are still exposed to risks. You should remain cautious if you are facing any ballistic threats.

    Knife/Edged Blade Protection Levels

    Contrary to popular belief, body armor is not just designed to protect against ballistic threats. Body armor can be used while facing other threats such as knife stabs and fire. In that regard, NIJ works with CAST to develop standards for body armor protection against knives and edged blades. A knife attack is not similar to a bullet attack. Body armor that can protect against a bullet will not necessarily be protective against a knife. That’s why edged blade protection levels are separate from the ballistic levels.

    The table below shows the various body armor edged blade protection levels.


    Knife Resistant Level 1 (KR1)

    Knife Resistant Level 2 (KR2)

    Energy Level






    5 m/sec

    6.2 m/sec

    5.9 m/sec

    7.3 m/sec

    Energy (Joules)





    Weapon Mass

    1.9 kg




    Maximum Penetration






    Edged blade protection levels are not very specific because they are largely dependent on how powerful the attacker is, and the size and weight of the weapons. These are factors that vary very widely. Each stab ever recorded will most likely have a different combination of weapon size and the attacker’s power. The attacker’s power or strength are depicted by the speed of at which the weapon is thrown or thrust. This speed and the weight of the weapon determines the energy on that weapon as it approaches, and hence how deep it can penetrate.

    An edged blade weighing 1.9 kg is used to test body armor and come up with the classifications outlined on the table above. Each level, KR1 and KR2, is further divided into two categories based on the amount of energy given to the weapon during the attack.

    KR1 (Knife Resistant Level 1)

    While testing body armor for KR1 certification, a 1.9 kg edged blade is given a speed of 5 m/sec, that translates into 24 joules of energy. This kind of attack should cause penetration of a maximum of 7mm into an effective KR1 vest.

    In another instance, the same edged blade is given a speed of 6.2 m/sec, which combines with its weight to deliver 36 joules of energy on it. This kind of attack will cause a maximum penetration of 20mm on body armor that has been certified as KR1 complaint.

    KR2 (Knife Resistant Level 2)

    KR2 also features the same testing concept and the same kind of weapon. In KR2 tests, the 1.9 kg blade is given a speed of 5.9 m/sec, which translates into 33 joules of energy. This kind of attack should not penetrate more than 7mm into KR2 body armor.

    The next test for KR2 body armor involves the same weapon, but this time with a speed of 7.3 m/sec and 50 joules of energy. This attack can only penetrate up to 20mm into KR2 body armor.

     Note that the levels discussed above only apply to soft body armor. The body armor is therefore quite thick, given it only made of aramid fibers. The fibers are very strong and stretchy, and they work by distributing and subduing the force on the weapon before it completely penetrates them. Comfort and ease of wear are the main motivation behind the development of the soft body armor for edged blade protection.

    The armor is quite effective against slash attacks. Slash attacks tend to have a lesser force and will, in most instances, just scrape the top layer of the body armor. Attacks with pointed and streamlined weapons such as arrowheads and knives tend to be more dangerous. With a good understanding of the standards above, if you know what kind of weapons are associated with the threats you are facing and how they are likely to be used, you can adequately protect yourself.

    As mentioned above, soft body armor for protection against edged blades and spiked weapons tend to be quite thick. It is therefore difficult to conceal. The armor is worn on top of your clothes in most cases. Hard body armor is the most protective against edged blades and spiked weapons. The ceramic or steel armor plates will easily stop the weapons.

    As mentioned earlier ballistic protection should never be equated to stab and spike protection. For instance, a small knife will easily penetrate through a level II bulletproof vest when thrusted hard at you. As such, it is important to understand the kind of threats you are facing and ensure the vests have adequate thickness if you choose to go with soft body armor. A level IIA carrier vest with a ceramic or steel armor plate is enough to stop a stabbing attack. Hard armor might, therefore, be the best option if you must conceal the body armor.

    Body armor that is designed to protect against edged blades and spiked weapons is generally used by law enforcement officers, prison warders, security guards and other people with similar responsibilities. Anyone is free to use such armor if they feel it’s necessary. For instance, knife crime has been on the rise in large European cities, especially London. Civilians in such places might, therefore, feel threatened and feel the need to wear body armor.

    Just as is the case with ballistic protection, no body armor can guarantee you 100% protection against edged blades or spiked weapons. Areas of your body that are not covered by the body armor are still vulnerable to these attacks. As such, body armor is not a ticket for you to get into dangerous situations or be reckless. People should always avoid all risky areas whenever possible.

    For instance, it is important that you do not fuel a confrontation when accosted by knife attackers. If they want to rob you, let them take whatever they can take. You’ll involve the authorities afterwards so that they can try and recover your belongings.

    You can find body armor of all types and protection levels on If you have any question or concern, get in touch with us via the email























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