In California, you can carry most folding pocketknives concealed in your pocket, and you can carry fixed-blade knives and locking folders openly in a visible sheath with no state-law limit on blade length. What you cannot do is conceal a fixed blade or a locked-open folder, and you cannot own or carry switchblades of two inches or longer, butterfly knives, ballistic knives, cane swords, or disguised blades like belt-buckle or lipstick knives. Schools, courthouses, federal buildings, and airports have their own stricter rules, and some cities, Los Angeles among them, flip the state rules on their head.
The Dirk or Dagger Rule Controls Concealed Carry
California’s knife rules revolve around one classification. Under Penal Code 16470, a “dirk or dagger” is any knife or instrument that can be readily used as a stabbing weapon capable of inflicting great bodily injury or death.1California Legislative Information. California Code PEN 16470 Every fixed-blade knife counts. So does any folding knife whose blade is exposed and locked into position.
Carrying a concealed dirk or dagger is a crime under Penal Code 21310.2California Legislative Information. California Code PEN 21310 Concealed means hidden from plain view: in a pocket, in a bag, under a jacket. The offense is a wobbler, which prosecutors can file as a misdemeanor punishable by up to a year in county jail or as a felony punishable by 16 months, two years, or three years in state prison.
Folding Pocketknives in Your Pocket
A folding knife that is closed is not a dirk or dagger. Penal Code 16470 says a nonlocking folding knife or pocketknife becomes a stabbing weapon only when the blade is exposed and locked open.1California Legislative Information. California Code PEN 16470 A standard pocketknife, a Swiss Army knife, or a utility knife is fine in your pocket as long as it stays folded.
The moment you lock the blade open and tuck the knife into your waistband or back pocket, the analysis changes. Now you are carrying a concealed dirk or dagger, and the exception no longer protects you. Keep folders closed when you carry them out of sight.
Fixed Blades and Locking Folders in the Open
Fixed-blade knives and locking folders are legal to carry openly, and state law sets no maximum blade length. A hunting knife or even a machete is permissible on a public street as long as it is visible. The usual method is a sheath worn on the belt.
Visibility is the whole point. Drop that same fixed-blade hunting knife into a backpack and you have converted a lawful open carry into an illegal concealed one. If you own a dirk, dagger, or fixed-blade knife and want to carry it, wear it where people can see it.
One caveat: state law gives you this freedom, but cities can take it back. Some California municipalities cap blade length for openly carried knives even though the state does not.
Knives That Are Always Illegal
Some knives are prohibited by their design, no matter how you carry them.
Switchblades and Butterfly Knives
Penal Code 21510 makes it a misdemeanor to carry on your person, keep in a vehicle, or sell a switchblade with a blade two inches or longer.3California Legislative Information. California Code PEN 21510 California defines switchblade broadly to include any pocketknife-style knife that opens automatically by button, handle pressure, a flick of the wrist, or gravity. A conviction can bring up to six months in jail and a fine of up to $1,000.
Butterfly knives (balisongs) fall under the same statute, because the blade deploys through a flipping motion using gravity and wrist action. A switchblade with a blade under two inches is technically legal under state law, but local ordinances or location-based rules may still prohibit it.
Ballistic Knives
Penal Code 21110 bans ballistic knives, which have a detachable blade propelled by a spring or similar mechanism. Making, importing, selling, giving, or possessing one is a wobbler, punishable as a misdemeanor by up to a year in jail or as a felony by up to three years in prison.
Cane Swords
Penal Code 20510 forbids manufacturing, importing, selling, giving, lending, or possessing a cane sword. It carries the same wobbler penalty range as the ballistic knife statute.4California Legislative Information. California Code PEN 20510
Disguised and Undetectable Knives
Belt-buckle knives are illegal to possess under Penal Code 20410. Lipstick-case knives and similar disguised blades fall under related prohibited-weapons statutes. The common thread is deception: a knife built to look like something else is treated as inherently dangerous.
Penal Code 20810 separately bans the commercial manufacture, import, or sale of knives that cannot be detected by a metal detector; any knife commercially made in California must contain detectable materials.5California Legislative Information. California Code PEN 20810 Violation is a misdemeanor.
Where Legal Knives Become Illegal
A knife that is lawful on the sidewalk can be a crime to carry once you step into certain buildings. The thresholds in these laws are much lower than what state carry law allows, and that is where people get caught.
K-12 Schools
Penal Code 626.10 bans a long list of items on the grounds of any public or private school serving kindergarten through 12th grade: dirks, daggers, any knife with a blade longer than two and a half inches, any folding knife with a locking blade, ice picks, unguarded razors, razor blades, and box cutters.6California Legislative Information. California Code PEN 626.10 A violation is punishable by up to a year in county jail. Notice the two-and-a-half-inch cap and the flat ban on locking folders: both are far stricter than general state law.
State and Local Government Buildings
Penal Code 171b prohibits bringing a knife with a blade longer than four inches into any state or local public building, or any meeting required to be open to the public.7California Legislative Information. California Code PEN 171b Courthouses, city halls, and similar facilities are covered. The restriction reaches any fixed blade or any blade that can be locked in position, so a large locking folder is included.
Federal Buildings and Post Offices
Under 18 U.S.C. § 930, possessing a dangerous weapon in a federal facility is a crime. The statute exempts pocketknives with a blade shorter than two and a half inches; anything bigger is prohibited.8Office of the Law Revision Counsel. 18 U.S. Code 930 – Possession of Firearms and Dangerous Weapons in Federal Facilities This covers federal courthouses, IRS offices, Social Security offices, and the like.
Post offices are stricter still. Federal regulations ban any weapon, including knives, on postal property, openly or concealed, with no blade-length exception.9eCFR. 39 CFR 232.1 – Conduct on Postal Property
Airports and Flights
TSA rules bar nearly all knives from carry-on luggage. The exceptions are round-bladed butter knives and plastic cutlery.10Transportation Security Administration. Sharp Objects Knives can go in checked baggage if they are sheathed or securely wrapped to protect handlers.11Transportation Security Administration. Knives – What Can I Bring? TSA officers have final say at the checkpoint.
Cities Can Be Stricter Than the State
California does not preempt local knife rules, so cities and counties can go further than state law. Los Angeles is the clearest example. L.A. Municipal Code Section 55.10 makes it illegal to carry in plain view any knife or dagger with a blade of three inches or longer on any public street or in any public place.12American Legal Publishing. Los Angeles Municipal Code SEC. 55.10 – Carry Knives or Daggers in Plain View Prohibited That inverts the state framework: California allows open carry of fixed-blade knives but bans concealing them, while Los Angeles bans openly carrying anything over three inches. The ordinance has exceptions for lawful occupations, lawful recreation, and recognized religious practice.
Other California cities have their own blade-length or carry-method rules. Before you rely on state law alone, check the municipal code for anywhere you plan to carry. A call to the local police non-emergency line is a cheap way to avoid an arrest that was never necessary.
Penalties
- Concealed dirk or dagger (PC 21310): wobbler, up to one year in county jail as a misdemeanor or 16 months, two years, or three years in state prison as a felony.2California Legislative Information. California Code PEN 21310
- Switchblade or butterfly knife with 2+ inch blade (PC 21510): misdemeanor, up to six months in jail and a fine of up to $1,000.3California Legislative Information. California Code PEN 21510
- Ballistic knife (PC 21110): wobbler, up to one year in jail or up to three years in prison.
- Cane sword (PC 20510): wobbler, up to one year in jail or up to three years in prison.4California Legislative Information. California Code PEN 20510
- Undetectable knife (PC 20810): misdemeanor.5California Legislative Information. California Code PEN 20810
- Knife on K-12 school grounds (PC 626.10): up to one year in county jail.6California Legislative Information. California Code PEN 626.10
- Knife over four inches in a public building (PC 171b): see statute.7California Legislative Information. California Code PEN 171b