Yes, you can carry a knife in Colorado, and in most cases you can carry it openly at any blade length. The main limit is concealment: hiding a dagger, dirk, knife, or stiletto with a blade longer than 3.5 inches is a class 1 misdemeanor unless an exception applies.1Justia. Colorado Revised Statutes Section 18-12-105 – Unlawfully Carrying a Concealed Weapon – Unlawful Possession of Weapons A few knife types are banned outright, schools and federal buildings are off-limits, and cities like Denver, Boulder, Aurora, and Lakewood add their own rules on top of state law.
Open Carry vs. Concealed Carry
Open carry of knives is broadly legal across Colorado at any length. A visible sheath on your belt, or a clip showing clearly on the outside of your pocket, is not concealment.2Colorado Bureau of Investigation. Colorado Revised Statutes 18-12-105 – Unlawfully Carrying a Concealed Weapon
A knife becomes “concealed” when it’s placed out of sight so it can’t be seen through ordinary observation. Inside a pocket, under a jacket, or tucked into a bag on your person all count. Once concealed, blade length becomes the deciding factor.
Colorado defines a “knife” for concealed-carry purposes as any dagger, dirk, knife, or stiletto with a blade over 3.5 inches, along with any other dangerous instrument capable of inflicting cutting, stabbing, or tearing wounds.3Justia. Colorado Revised Statutes Section 18-12-101 – Peace Officer Affirmative Defense – Definitions That catch-all matters. A shorter blade can still qualify if it’s being carried as a weapon capable of serious cutting or stabbing injury.
The statute doesn’t spell out how blade length is measured, which leaves some gray area at the margin. If your knife sits close to 3.5 inches, staying comfortably under the line is the safer approach than relying on a favorable measurement in court.
When You Can Conceal a Longer Blade
The 3.5-inch limit doesn’t apply everywhere. State law carves out three situations where you can conceal a longer blade legally:
- In your own home, at your place of business, or on property you own or control.1Justia. Colorado Revised Statutes Section 18-12-105 – Unlawfully Carrying a Concealed Weapon – Unlawful Possession of Weapons
- In a private vehicle, when the knife is carried for lawful protection of yourself, another person, or property while traveling. This vehicle exception is the one statewide preemption for knives: it applies even when you drive through a city with stricter rules.1Justia. Colorado Revised Statutes Section 18-12-105 – Unlawfully Carrying a Concealed Weapon – Unlawful Possession of Weapons4American Knife and Tool Institute. Colorado Knife Laws
- When the knife is being used for hunting or fishing. Sporting knives are excluded from the statutory definition entirely, but this functions as an affirmative defense.3Justia. Colorado Revised Statutes Section 18-12-101 – Peace Officer Affirmative Defense – Definitions
The affirmative-defense piece is worth understanding. It doesn’t stop an officer from citing or arresting you. You can raise the defense in court, but the burden is on you to show the knife was genuinely for hunting or fishing. A fillet knife in a tackle box next to your rod and license tells a cleaner story than the same knife loose in your coat at a convenience store.
Knife Types That Are Banned or Restricted
Colorado bans a short list of weapons as “illegal weapons”: blackjacks, gas guns, metallic knuckles, and ballistic knives.5Justia. Colorado Revised Statutes Section 18-12-102 – Possessing a Dangerous or Illegal Weapon – Affirmative Defense – Definition The ballistic knife is the only knife in that group. It’s defined as a knife with a blade that shoots out of the handle using a spring-loaded device or an explosive charge.6Colorado Bureau of Investigation. Colorado Revised Statutes 18-12-101 – Definitions Knowingly possessing one is a class 1 misdemeanor regardless of where you are or how you carry it.
Switchblades and gravity knives used to be illegal in Colorado. The legislature removed both from the “illegal weapon” definition in 2017 with SB17-008, so under state law you can now own and carry either.7Colorado General Assembly. SB17-008 Legalize Gravity Knives and Switchblades Several cities, however, kept their local bans in place. More on that below.
Assisted-opening knives are a separate category and have never been restricted in Colorado. The distinction: a switchblade deploys the blade entirely by pressing a button, while an assisted opener requires you to physically start the blade moving with a thumb stud or flipper before a spring finishes the motion. If a button alone does the job, it’s a switchblade. If you have to push on the blade to start it, it’s an assisted opener.
Where You Can’t Carry At All
Some places are off-limits regardless of blade length or how the knife is carried.
Schools, Colleges, and Universities
Bringing a deadly weapon other than a firearm onto the grounds of any public or private elementary, middle, junior high, high, or vocational school, or any college, university, or seminary, is a class 6 felony in Colorado.8Justia. Colorado Revised Statutes Section 18-12-105.5 – Unlawfully Carrying a Weapon – School, College, or University Grounds “Deadly weapon” covers any knife or instrument used or intended to be used in a way capable of producing death or serious bodily injury.9Justia. Colorado Revised Statutes Section 18-1-901 – Definitions A pocketknife forgotten in a backpack can fall within this definition depending on the circumstances, and enforcement is strict.
Narrow exceptions exist for authorized educational demonstrations, employees whose job duties require a blade, and approved extracurricular or athletic activities.8Justia. Colorado Revised Statutes Section 18-12-105.5 – Unlawfully Carrying a Weapon – School, College, or University Grounds Outside those, leave the knife at home or locked in your car before you step onto school property.
Federal Buildings
Federal facilities in Colorado follow federal rules, not state knife law. Under 18 U.S.C. ยง 930, bringing a dangerous weapon into a federal facility is a crime carrying up to one year in prison, and up to two years in a federal courthouse. The statute exempts pocketknives with blades under 2.5 inches, a full inch shorter than Colorado’s concealed-carry threshold.10Office of the Law Revision Counsel. 18 USC 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities
The Interagency Security Committee screening standard prohibits bladed items with blades over 2.5 inches and razor-type blades such as box cutters at any length.11National Archives. Items Prohibited in Federal Facilities – An ISC Standard 2022 Edition At a post office, Social Security office, VA clinic, or federal courthouse, assume anything larger than a small pocketknife will be taken at the door.
Airports and Aircraft
TSA allows no knives in carry-on bags. You can pack knives in checked luggage if they’re sheathed or securely wrapped to protect baggage handlers, and the TSA officer at the checkpoint has final say on any item.12Transportation Security Administration. Knives
Penalties If You Get It Wrong
The consequences depend heavily on the charge:
- Concealed carry of a knife over 3.5 inches is a class 1 misdemeanor, carrying up to 364 days in jail and a fine of up to $1,000.1Justia. Colorado Revised Statutes Section 18-12-105 – Unlawfully Carrying a Concealed Weapon – Unlawful Possession of Weapons
- Possessing a ballistic knife or other illegal weapon is also a class 1 misdemeanor with the same range.5Justia. Colorado Revised Statutes Section 18-12-102 – Possessing a Dangerous or Illegal Weapon – Affirmative Defense – Definition
- Carrying a deadly weapon on school grounds is a class 6 felony: one to 18 months in prison, a fine between $1,000 and $100,000, and one year of mandatory parole after release.13Justia. Colorado Revised Statutes Section 18-1.3-401 – Felonies – Classification – Presumptive Penalties
The jump from misdemeanor to felony is the real exposure. A misdemeanor concealed-carry charge sometimes gets pleaded down. A felony conviction for a weapon on school grounds follows you on background checks and can affect employment, housing, and gun ownership for life.
Check the City Before You Carry
Colorado does not broadly preempt local knife regulations. Outside the private-vehicle exception, each city can set its own rules, and several have.4American Knife and Tool Institute. Colorado Knife Laws
Denver bans automatic knives entirely under its municipal code, even though switchblades have been legal statewide since 2017. Aurora and Lakewood maintain their own switchblade bans. Boulder and Colorado Springs restrict carrying any concealed knife, not just those over 3.5 inches, and both cities also prohibit displaying a knife in a way that threatens or alarms others.14American Knife and Tool Institute. Preemption Law and Knives Before carrying in any Colorado city, read that city’s municipal code. State legality alone will not protect you.