What Knives Are Illegal in Colorado: Bans, Carry Limits, and Penalties

Colorado bans only one knife outright: the ballistic knife. Every other knife is legal to own, so the real question of what knives are illegal in Colorado is a question about how and where you carry them. Concealed carry of a knife with a blade longer than three and a half inches is a crime, deadly weapons are off-limits on school grounds, and a handful of cities restrict knives that state law otherwise permits.

The Only Knife Banned Outright

Colorado’s “illegal weapons” list includes exactly one knife: the ballistic knife, defined as any knife with a blade that can be forcefully launched from the handle by a spring-loaded mechanism or explosive charge. Simply possessing one is a Class 1 misdemeanor, punishable by up to 364 days in jail and a fine of up to $1,000.1Justia. Colorado Code 18-12-102 – Possessing Dangerous or Illegal Weapons

Nothing else is banned statewide. Daggers, stilettos, dirks, fixed-blade knives, folding knives, and multi-tools are all legal to own. For every knife besides the ballistic knife, the question is not whether you can have it but how you can carry it.

Switchblades, Gravity Knives, and Butterfly Knives

Switchblades and gravity knives used to sit on the illegal weapons list. Senate Bill 17-008 removed them in 2017, making them legal under state law to own and to carry openly.2Colorado General Assembly. SB17-008 – Legalize Gravity Knives and Switchblades That change only reaches state law. Some cities still prohibit them, and Denver’s municipal code is the most important example.

There is also a federal rule to know about. The Switchblade Knife Act makes it illegal to transport switchblades, gravity knives, or butterfly knives across state lines as part of a commercial transaction, with a penalty of up to $2,000 in fines, up to five years in prison, or both.3Office of the Law Revision Counsel. 15 USC 1242 – Introduction, Manufacture for Introduction, Transportation or Distribution in Interstate Commerce It does not restrict personal possession or carrying within a single state; it reaches buying, selling, and shipping between states.

The 3.5-Inch Concealed Carry Rule

The restriction most Colorado knife owners actually run into is concealed carry. Carrying a concealed knife is a Class 1 misdemeanor when the blade qualifies as a “knife” under state law. The statutory definition covers any dagger, dirk, knife, or stiletto with a blade over three and a half inches, along with any other dangerous instrument capable of inflicting cutting, stabbing, or tearing wounds.4Justia. Colorado Code 18-12-101 – Peace Officer Affirmative Defense – Definitions “Concealed” means hidden from ordinary observation: in a pocket, inside a bag, or under clothing.

There is no concealed-carry permit for knives in Colorado. The state issues concealed handgun permits, and the concealed carry statute makes clear that its permit exception applies only when “the weapon involved was a handgun.”5Justia. Colorado Code 18-12-105 – Unlawfully Carrying a Concealed Weapon Carrying a knife openly on a belt sheath or other visible position is generally lawful regardless of blade length, because the concealed carry statute only targets concealment.

When the Concealed Carry Ban Doesn’t Apply

The prohibition has several carve-outs:

  • In your own home, place of business, or on property you control, you can carry a concealed knife of any size.
  • In a private vehicle, a person may carry a concealed weapon for lawful protection of themselves or others while traveling.
  • Hunting and fishing knives are carved out of the statutory definition of “knife” when carried for sporting use, so they can be concealed regardless of blade length. This is an affirmative defense, which means you carry the burden of proving it if charged.

The vehicle exception is the one people rely on most. Notice the specific language: the weapon must be carried “for lawful protection” while “traveling.” A knife in the glove box during a road trip fits comfortably. Whether the same knife in a car parked at a bar still qualifies is less clear, and the statute does not spell out where the line falls.5Justia. Colorado Code 18-12-105 – Unlawfully Carrying a Concealed Weapon

The Pocket Clip Question

One ambiguity comes up constantly: is a folding knife held in place by a pocket clip “concealed” or “openly carried”? If the clip is visible but the blade and most of the handle sit inside the pocket, reasonable people disagree. Colorado courts have not issued a definitive ruling. Some other states have found that a visible clip is enough to count as open carry, but that reasoning is not guaranteed to hold here. If you are carrying a blade over three and a half inches and relying on a pocket clip to keep you legal, you are betting on how an officer or judge interprets “concealed.”

Places Where Even a Legal Knife Becomes a Crime

A knife that is perfectly legal to carry on the sidewalk can become a felony inside the wrong building.

School Grounds

Colorado prohibits carrying any “deadly weapon” that is not a firearm on the grounds of any public or private school, from elementary through university. The offense is a Class 6 felony, carrying one to eighteen months in prison, a mandatory one-year parole period, and a fine between $1,000 and $100,000.6Justia. Colorado Code 18-12-105.5 – Unlawfully Carrying a Weapon on School Grounds7Justia. Colorado Code 18-1.3-401 – Felonies – Classification – Presumptive Penalties

One important detail: the statute uses “deadly weapon,” not “knife.” Colorado courts have held that a knife with a blade under three and a half inches is not automatically a deadly weapon unless the person used or intended to use it as one. A larger knife or a fixed-blade fighting knife would almost certainly qualify. The exceptions are narrow: authorized educational demonstrations, job duties that require the tool, and participation in authorized extracurricular activities.6Justia. Colorado Code 18-12-105.5 – Unlawfully Carrying a Weapon on School Grounds

Legislative and Federal Buildings

A separate section of the concealed weapons statute makes it a Class 1 misdemeanor to carry any explosive, incendiary device, or other dangerous device into the buildings housing the General Assembly’s chambers, galleries, offices, or legislative hearings without legal authority.5Justia. Colorado Code 18-12-105 – Unlawfully Carrying a Concealed Weapon In practice, many courthouses and government buildings screen visitors through metal detectors and confiscate knives under their own security policies regardless of what the statute says.

Federal property follows federal law. Post offices, federal courthouses, and other federal buildings generally prohibit dangerous weapons including knives under their own security regulations, even if you are legally carrying under Colorado law.

Local Rules That Go Further Than the State

Colorado does not have a statewide preemption law blocking cities from restricting knives beyond state law. Several cities use that authority aggressively.

  • Denver’s municipal code still makes automatic knives, including switchblades, unlawful even though state law legalized them in 2017. A switchblade bought legally elsewhere in Colorado can be cited inside Denver city limits.
  • Boulder and Colorado Springs both restrict concealed carry of any knife regardless of blade length, and both prohibit displaying a knife in a way that intimidates, threatens, alarms, or frightens another person.

Other municipalities may have their own rules covering public parks, city-owned buildings, or special events. The safest practice when traveling between Colorado cities is to check the local municipal code before assuming state law is all that applies.

Penalties

Local ordinance violations carry penalties set by the municipality, usually treated as infractions or misdemeanors with fines. A conviction on any of these charges also creates a criminal record that can affect employment, housing, and future background checks, which is often a more lasting consequence than the sentence itself.