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Can Body Armor Protect Against Knives?

Can body armor protect against knives? Only armor tested to a stab standard has a stab rating. What NIJ 0115.00 and the UK Home Office standard test, and why a ballistic rating is not a stab rating.

ArmorList Editorial·October 14, 2024·5 min read

A common question in personal security is: Can body armor protect against knives? Whether you're a law enforcement officer, security personnel, or a civilian focused on personal safety, the answer depends on what the armor was tested against. Stopping bullets and stopping blades are tested separately, and a vest has a stab rating only if that model was tested to a stab standard.

The research on body armor in general is worth knowing. In a study funded by the National Institute of Justice (NIJ), Liu and Taylor (2017) analyzed FBI data on officers assaulted with firearms or cutting instruments and killed or severely injured from 2002 to 2011, and found that among the 637 officers shot in the torso, those wearing body armor were 76 percent less likely to be killed than those without it. That figure is about gunshots to the torso; it does not measure protection against knives. Let's look at what the standards say about blades.

Understanding Body Armor

Body armor is rated against the threats named in the standard it was tested to. NIJ certifies body armor for law enforcement model by model: ballistic armor under NIJ 0101.06 and 0101.07, and stab armor on its own list, under NIJ 0115.00.

NIJ describes soft ballistic armor as working by catching the bullet in a web of very strong fibers that absorb and disperse its energy. Body armor is worn by law enforcement and the military, and it is also sold to civilians.

Stab-resistant armor is a separate category. NIJ Standard 0115.00, Stab Resistance of Personal Body Armor (September 2000), sets minimum performance requirements for armor that protects the torso against stab threats, and its scope is limited to stab resistance: it does not address ballistic threats.

For more on the materials, you might want to explore Materials Used in Armor Plates Explained.

Knife vs Bulletproof

A key distinction lies between a ballistic rating and a stab rating. A vest listed on the ballistic CPL at a handgun level is not stab-rated unless that model was also tested to a stab standard. NIJ lists stab-resistant models on their own list.

The UK guidance says the same from the other side. The UK's National Protective Security Authority (NPSA) advises that bullet-resistant body armour will not necessarily defeat a knife or a spike. Whether a given ballistic vest offers any knife resistance is not something its ballistic rating tells you.

For protection against knives, look for a stab rating, from a named standard, for the exact model. If you're interested in the differences between these types of armor, consider reading The Difference Between Ballistic and Stab-Resistant Armor.

Materials Matter

Makers build stab-resistant armor from different materials and constructions, and they describe them in their own terms. Kevlar is a para-aramid fiber that Stephanie Kwolek invented at DuPont in 1965 (the brand now belongs to Arclin), and Dyneema is a trademark for an ultra-high-molecular-weight polyethylene (UHMWPE) fiber; the names identify fiber families, not the quality of a given product.

We found no NIJ or Home Office source that ranks aramid, polyethylene, ceramic or steel for knife resistance (checked 1 October 2026). A material name does not tell you whether a model resists a blade. The stab rating of the exact model does.

For a deeper dive into Kevlar, check out How Effective Is Kevlar in Body Armor?.

Spike Ratings Explained

NIJ Standard 0115.00 has two protection classes. NIJ describes the edged blade class as the threats police officers face on the street, from high-quality, commercially made knives, and the spike class as the threats it expects in a corrections environment, from lower-quality knife blades and improvised spikes. Each class has three protection levels, based on the armor's ability to prevent a perforation deep enough to injure internal organs, with each level tested at a higher strike energy than the one below it.

The UK uses its own levels. The Home Office Body Armour Standard sets knife-resistance (KR) and spike-resistance (SP) levels, such as KR1 and SP1, alongside its ballistic levels in one document. A UK level and an NIJ level are set by different standards; neither converts into the other.

A stab rating is a class and a level. Check which class and which level a model is listed for on NIJ's stab list, with the date you read it, or which KR and SP levels it was certified to under the Home Office standard.

For more on body armor ratings, visit Understanding Body Armor Ratings.

Choosing the Right Armor

The steps below are our advice.

First, identify the threat: edged blades, spikes, or both, and whether firearms are also a risk. Then look for the class and level that match it. A higher level in NIJ 0115.00 is tested at a higher strike energy. In our view, weight and bulk matter too, because armor that is too heavy to wear all shift is armor left in the locker.

If you need protection against both blades and bullets, CJTTEC keeps a separate list for combination armor: the models on it went through full testing in both the ballistic and the stab Compliance Testing Programs and received a separate Notice of Compliance for each.

Always ensure the armor fits properly and covers the areas it was designed to cover. For tips on proper fitting, you might find The Right Way to Fit Body Armor helpful.

Limitations of Body Armor

A stab rating describes how a model performed against the test blades or spikes, at the test energies, in the standard it was tested to. It does not cover every blade, every angle or every force, and no armor is a promise of safety.

In our view, body armor is one part of a personal protection plan, not the whole of it.

Conclusion

Body armor protects against knives only to the extent that the exact model was tested to a stab standard. A ballistic rating is not a stab rating. Check the class and level on NIJ's stab list, or the KR and SP levels under the Home Office standard, for the model you are buying, with the date you read it.

Sources

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