Can Body Armor Stop A Knife – Bullet proof vs. stab proof

Have you ever wondered what body armor can protect you from? If it can stop a bullet, what else can it stop?

Level III and Level IV armor can stop a knife. Level IIA, Level II, and Level IIIA body armor can add some protection from a knife but it isn’t designed for it. If you want soft body armor with stab protection, you need to get armor specifically made to stop a knife.

The Difference Between Stab Proof and Bullet Proof

Body armor is usually rated according to NIJ standards to stop a certain caliber of a bullet traveling at a certain speed. Body armor tested this way does not have a stab-proof rating as well unless it is tested to the NIJ standards for stab resistance as well.

The NIJ has three levels of stab resistance that it tests. Level I is designed to stop low energy knife attacks, level II is tested to stop medium power knife attacks and level III is tested to stop the highest level of knife attacks.

The main way that soft armor stops bullets is by blunting the bullet and absorbing the energy of the blunted bullet. When a knife stabs a similar material, it spreads the tight weave of the fibers and lets the blade pass straight through.

NIJ Stab Resistant Armor Rating Resistance Level
Level I 17.7 ft/lb with 1/4 inch of penetration and 26.6 ft/lb with 3/4 inch of penetration.
Level II 24.3 ft/lb with 1/4 inch of penetration and 36.9 ft/lb with 3/4 inch of penetration.
Level III 31.7 ft/lb with 1/4 inch of penetration and 47.9 ft/lb with 3/4 inch of penetration.

To make soft armor stab-proof, manufacturers will add things like chain mail, metal inserts, or plastic inserts to their armor. This puts a physical barrier in the way of the blade as it tries to pass thought the armor and keeps the armor flexible.

Body armor designed to stop more powerful rounds like those from a rifle will usually stop a knife attack. They aren’t tested against knives and aren’t specifically rated to stop them but they are made of materials that are usually too strong for a knife to penetrate.

Stab-proof vests are most often used in countries like the UK and New Zealand where the threat of being shot is much lower than it is in the United States. In those countries, police, paramedics, and most others that work in the emergency response area all wear stab protective vests. In the U.S. police officers typically wear vests that offer ballistic protection instead of knife resistance since getting shot is much more likely for them.

AR 500 Armor and Spartan Armor Systems both sell high-quality body armor of all types.

Can a Knife Cut Through Kevlar?

Kevlar is a modern ballistic material designed to have a high strength even when it’s spun into very light fibers. These fibers can then be tightly woven into sheets and stacked on top of one another. When they’re stacked this way, this relatively light armor panel can stop pistol rounds and frag from explosive devices.

When Kevlar armor is attacked by a knife, it acts in a very similar way that other tightly woven materials do, it gets cut. These armor plates do provide a higher level of protection than simple cotton material but it isn’t enough to call it slash-proof and it’s still very susceptible to stabbing.

Is Wearing a Bulletproof Vest Illegal?

The laws regarding bulletproof vests vary depending on the country and even the area of the country. In the U.S., it is mostly legal for anyone to wear bulletproof vests unless they are a convicted felon. In certain states, it is also illegal to wear bulletproof vests on school grounds.

Other states have various rules on the wear of body armor. Connecticut for example only allows the sale of body armor in face to face sales.

This is just informational and not intended to be legal advice.

Even where wearing body armor is legal, you’re probably going to attract a lot of unwanted attention if you’re running around town wearing heavy body armor. People are likely to treat you as if you’re going to commit a crime or have committed a crime if it’s obvious that you’re wearing armor.

Backpack body armor is a great way to carry concealed armor without having to wear it all day long.

I’d recommend wearing concealable body armor if this is something you’re looking to avoid.

Related Questions

Can a bulletproof vest stop an arrow? When an arrow strikes soft body armor it separates the ballistic fibers of the armor panel apart and lets the arrow pass through. Soft armor provides some protection but it isn’t to a level that can be considered “arrow proof.” Hard armor will stop an arrow because it can’t be penetrated by the arrow.

How does a bulletproof vest stop a bullet? Bulletproof vests stop a bullet be cathing it and mushrooming it into a dish shape. This spreads the force it exerts on the armor panel across a larger area that the strong ballistic fibers can slow down and stop before it completely penetrates the armor panel.


A lot of people want to know if body armor can stop a knife. As you’ve probably already seen, there isn’t a simple yes or no answer to this question. It all depends on the type of body armor.

Soft body armor is going to protect you from a knife a lot better than simple clothing will, but it isn’t going to completely stop a knife unless it’s designed to.

Hard body armor will stop a knife.

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