When Can You Use a Knife in Self-Defense?

While self-defense is a constitutional right enshrined under the Second Amendment, the practical legality of using a knife depends on multiple factors. These include the circumstances of your self-defense situation and your local and state laws. Some jurisdictions may regulate knife ownership and carrying, even if self-defense is permitted.

Understanding local and state knife laws and regulations is crucial when building your self-defense plan and incorporating a knife into your everyday carry (EDC) kit. 

How is Self-Defense Legally Defined?

Self-defense is the act of using some force, up to and including lethal force, to protect yourself or others, such as loved ones, from imminent harm due to another person.

In law, self-defense is a type of legal defense used in court to demonstrate the use of force, and the exact amount used was justifiable due to the circumstances at the time.

Self-defense claims must meet three general principles to be valid:

• There must be a threat to the person claiming self-defense, such as a threat of death or grievous bodily harm.
• The threat must be immediate or imminent, meaning the defending person is being attacked or about to be attacked.
• The person defending themselves must have a reasonable belief that the amount of force they used was necessary to stop the attack.

When asking yourself, “In what situations is it legal to use a knife in self-defense,” check all applicable local and state laws. Each jurisdiction provides different rules and parameters that can change or modify the requirements for a self-defense claim to be valid.

When Can You Legally Use a Knife as a Self-Defense Weapon?

Americans interested in self-protection will carry two broad categories of weapons: less-than-lethal and lethal force, also called deadly force. While some may carry one or the other, the best-equipped will have at least one of each category. This approach is ideal for responding to situations of different severity levels with the proper force.

In the United States, the most prevalent lethal force weapon used in self-defense is a firearm; a common alternative is a knife. Most people consider the knife a tool, and many carry it for reasons other than self-protection. However, it is crucial to remember that, when used in self-defense, the knife is a lethal force weapon in all jurisdictions of the United States, from federal to local.

In principle, the answer to “When can you use a knife in self-defense?” is relatively simple. You can theoretically use a knife in self-defense if lethal force is appropriate.

In restrictive states, law enforcement may charge you for breaking the law if you use a knife the local jurisdiction classifies as illegal, even if the use of force was justified.

• Example: California restricts switchblades (CA Penal Code 17235) except for models with non-locking, folding blades with a length of 2” or less. Using a folding knife with a blade length of 4” for self-defense in California can potentially result in an illegal weapons charge.

Remember that even if your knife is legal and your use of force is theoretically legitimate under the letter of the law, you may still face legal challenges and potential convictions. Consider seeking competent legal representation from a self-defense lawyer to protect your rights in court, especially in a jurisdiction with restrictive laws, Soros-funded DAs , or anti-self-defense judges.

What Types of Knives Can I Use in Self-Defense?

While no federal laws restrict the types of knives you can use or carry, local and state laws may have rules regulating which knives you can use in self-defense. Knife laws in the United States generally fall into one of three categories: possession, sale/transfer, and carry laws.

Knife Possession Laws

In some states, “When can you use a knife in self-defense?” depends on which knives are legal to own in your area.

Laws regulating the possession of specific types of knives restrict individuals from owning them within a given city, county, or state. Using a banned or restricted knife in self-defense can result in an illegal weapons charge or invalidate your self-defense claim, even if you were otherwise justified.

• Example: Switchblades are illegal in New York City. The city defines a switchblade as any knife with an automatic blade opening mechanism via a button, spring, or another device in the knife handle.

Knife Sale and Transfer Laws

Some jurisdictions may regulate sales and transfers of specific knife types. If there is no law against possessing such knives, a sale or transfer law typically makes it legal for a resident to own them but not to buy or receive them from another person. 

One of the most common types of knife sale and transfer laws is an age restriction, preventing individuals and businesses from selling knives to people under a specific age.

• Example: In Florida (FL Statutes 790.17), furnishing any “dirk, electric weapon or device, or other weapons,” including knives, to minors under 18 is illegal. There is an exception for what the state describes as “ordinary pocket knives” or “common pocket knives.”

Knife Carry Laws

Many states, counties, cities, and jurisdictions regulate the right to carry knives in public. Knowing your knife carry laws is crucial if you plan to add one to your everyday carry (EDC) kit, especially for self-defense applications.

As with firearms, each state may regulate the legality of open and concealed knife carry, imposing specific rules and requirements for each case. For instance, a particular state or area may make it illegal to open-carry a knife but allows concealed-carrying if the owner has a valid concealed weapons permit.  

Verify whether your state’s concealed carry permit covers non-firearms such as knives. For example, the Colorado Handgun Permit (CHP) only covers handguns. You are bound to the state’s laws on concealed knives (CO Revised Statutes 18-12-101(f)) regardless of whether or not you have a CHP. 

In addition to these rules, there may be location-based restrictions preventing the carrying of any knives in specifically designated areas. Commonly restricted areas include government buildings, schools, courthouses, police stations, and public transportation.

• Example: In New Mexico (NM Statutes 30-7-13), boarding a bus while possessing a readily-available “firearm or other deadly weapon” on your person is illegal.

Duty to Retreat vs. Stand Your Ground

Depending on your state of residence, a critical element of your self-defense claim is whether your local or state laws fall under the duty-to-retreat or stand your ground principle.

Duty to Retreat

Under U.S. law, the duty to retreat is the common name given to a legal parameter for self-defense claims. In a duty to retreat state, a self-defense claimant must reasonably attempt to avoid or retreat from a confrontation or potential threat before resorting to force. This principle discourages using force as a first resort, even if it would be otherwise justified.

Most duty to retreat states carve out an exception for home defense under the principle of castle doctrine, meaning there is no duty to retreat from a threat in your own home. In some jurisdictions, castle doctrine extends to your vehicle.

Examples of states with a duty to retreat:

• Connecticut
• Delaware
• Massachusetts
• Minnesota
• Virginia
• Washington 

Stand Your Ground

The stand your ground principle removes the duty to retreat. It allows someone under imminent threat not to prioritize avoiding or retreating from it before resorting to force, including in public settings outside the home.

Theoretically, standing your ground lets someone choose to use force to defend themselves, even if a safe way to retreat is available.

Examples of states with stand your ground legislation:

• Arizona
• Florida
• Kansas
• Georgia
• New Mexico
• Wyoming

Can You Stab Someone in Self-Defense?

The presence or use of a knife during a self-defense situation may not necessarily indicate force. If the intended use at the time of the confrontation was not to harm another person, it is generally not considered lethal force.

However, using a knife to defend yourself during a confrontation falls under the use-of-force principle. When used as a weapon, the knife is generally considered lethal, regardless of how it is used or whether the person using it successfully hits another. If lethal force is justifiable, it means that, theoretically, any use of the knife, including slashing or stabbing motion, can be done in self-defense.

What Can Happen if You Pull a Knife Out on Someone in Self-Defense, But Do Not Use It?

One of the most common mistakes made by individuals interested in self-defense is planning to use their weapon for intimidation. It is generally inadvisable to pull any lethal weapon out without intent to use it, even against people who may legitimately threaten you or if harm is imminent.

Most self-defense situations assume that if force, including lethal force, is necessary, it may only be used immediately to stop an imminent threat.

Pulling a knife out and not using it is the equivalent of showing or pulling a firearm in front of someone else; doing so may be considered brandishing instead of self-defense. The difference exists because displaying weapons in a threatening manner, even against a potentially dangerous person, implies there was no imminent threat. Brandishing can invalidate your self-defense claim, potentially resulting in legal charges.

If you must pull your knife out, you should only do so when your life or that of another is in danger. Avoid using your knife to issue a warning or threaten another person.

Dependable Self Defense Knives at Uppercut Tactical

Uppercut Tactical carries a selection of quality tactical and EDC knives suitable for any application. Whether you need a simple cutting tool, a survival and bushcraft knife, or a reliable self-defense knife, our knives are designed to help you meet your needs and keep you safe.