California does not impose one single statewide blade-length cap for all knives. Instead, the law turns on knife type, how it is carried, and where it is carried. Most ordinary folding knives and many fixed blades are lawful to own, but concealed carry of a dirk or dagger is generally prohibited, switchblades with blades of two inches or more are restricted, and schools, public buildings, Capitol areas, and airport sterile areas have their own rules. (Legislative Information)
This article provides legal information, not legal advice.
Quick Answer
California knife law is category-based, carry-based, and location-based. (Legislative Information)
That means three questions usually control the analysis: what kind of knife is involved, whether it is carried openly or concealed, and whether the person is in a restricted place such as a school, a state or local public building, the State Capitol area, or an airport sterile area. California also separately prohibits certain disguised knives and ballistic knives statewide. (Legislative Information)
Most ordinary knives are legal to own in California, but several specific categories are prohibited. (Legislative Information)
Ordinary folding knives, kitchen knives, hunting knives, and most fixed-blade knives are not broadly banned from ownership by the California statutes reviewed here. The stronger statewide prohibitions apply to ballistic knives under Pen. Code § 21110 and to disguised knives such as air gauge knives, belt buckle knives, cane swords, and lipstick case knives under Pen. Code §§ 20310, 20410, 20510, and 20610. (Legislative Information)
The switchblade rule is narrower than a blanket ownership ban. California defines a “switchblade knife” as a knife with a blade two or more inches long that opens automatically in the ways listed in Pen. Code § 17235, and Pen. Code § 21510 criminalizes carrying one on the person, keeping one in the passenger or driver area of a vehicle in public, and selling or transferring one. That section does not read like a general statewide ban on mere possession in every setting. (Legislative Information)
Undetectable knives are also regulated differently from ballistic knives. Pen. Code § 20810 chiefly targets commercial manufacture, import, export, and sale, and requires commercially manufactured stabbing weapons to include detectable material. The reviewed statute does not create the same broad possession ban that applies to ballistic knives. (Legislative Information)
Often yes, but California’s clearest statewide protection is for a knife openly carried in a waist sheath, and local ordinances can be stricter. (Legislative Information)
Pen. Code § 20200 says a knife carried in a sheath worn openly suspended from the waist is not concealed for purposes including Pen. Code § 21310. That makes openly worn fixed blades the safest statewide carry posture under California law. By contrast, a fixed blade or other knife that qualifies as a dirk or dagger becomes risky when hidden from view. (Legislative Information)
Open carry is not unlimited. Los Angeles city law prohibits carrying in plain view any knife or dagger covered by its ordinance on public streets and other public places, and Los Angeles County has a similar plain-view restriction in unincorporated county areas. (American Legal Publishing)
Usually, only some folding knives; concealed carry of a dirk or dagger is generally illegal. (Legislative Information)
Pen. Code § 21310 makes it a crime to carry concealed upon the person any dirk or dagger. Pen. Code § 16470 defines “dirk” or “dagger” broadly as a stabbing weapon capable of inflicting great bodily injury or death, but it also says a nonlocking folding knife, a folding knife not prohibited by Pen. Code § 21510, or a pocketknife counts only if the blade is exposed and locked into position. In practical terms, a closed folding knife is much safer for concealed carry analysis than a fixed blade or an open-and-locked folding knife. (Legislative Information)
Vehicle carry also matters. A switchblade with a blade of two inches or more may not be possessed in the passenger’s or driver’s area of a motor vehicle in a public place, and it may not be carried on the person. (Legislative Information)
Automatic knives are the most restricted category; butterfly and double-edged knives are not banned by name statewide, but carry rules still matter. (Legislative Information)
Under Pen. Code §§ 17235 and 21510, California’s switchblade rules apply to automatic knives with blades two inches or more in length. That covers many push-button and some out-the-front designs. The statute does not define sub-two-inch automatics as switchblades for that statewide offense. (Legislative Information)
California’s reviewed statewide knife statutes do not specifically name butterfly or balisong knives as prohibited weapons, and they do not ban double-edged knives by name. But if a butterfly knife or double-edged knife is carried in a way that makes it a ready stabbing weapon, it can fall into the dirk-or-dagger analysis, which makes concealed carry the real statewide problem. (Legislative Information)
Not as a single statewide rule for all knives, but California uses several blade-length thresholds in specific contexts. (Legislative Information)
The most important thresholds are these: two inches for the statewide switchblade definition and offense in Pen. Code §§ 17235 and 21510; two and one-half inches for several school and campus restrictions in Pen. Code § 626.10; and four inches for certain knives in state or local public buildings, open public meetings, Capitol-related locations, and airport sterile areas under Pen. Code §§ 171b, 171c, and 171.5. So the right answer to “What blade length is legal in California?” is usually “legal where, and for what kind of knife?” (Legislative Information)
California restricts knives most heavily in schools, college campuses, public buildings, Capitol areas, and airport sterile areas. (Legislative Information)
For K-12 schools, Pen. Code § 626.10 prohibits bringing or possessing, among other things, any dirk or dagger, ice pick, knife with a blade longer than 2.5 inches, locking folding knife, unguarded razor, razor blade, or box cutter on school grounds, subject to listed exceptions. For private universities, UC, CSU, and community colleges, the section prohibits dirks, daggers, ice picks, and fixed blades longer than 2.5 inches, again with listed exceptions for school activities, employment, residences, and food preparation or consumption. (Legislative Information)
Pen. Code § 171b restricts certain knives over four inches in state or local public buildings and at meetings required to be open to the public. Pen. Code § 171c does the same in the State Capitol, certain legislative offices and hearing rooms, and on Capitol grounds when posted. Pen. Code § 171.5 restricts knives over four inches, plus box cutters and straight razors, in airport sterile areas and passenger vessel terminals. (Legislative Information)
The reviewed statutes do not show a general statewide minimum age for ordinary knives, but California does restrict sales and transfers of certain knives and heavily regulates knives at schools. (Legislative Information)
The clearest statewide sale rule in the knife statutes reviewed here is Pen. Code § 21510(c), which prohibits selling, offering for sale, transferring, lending, or giving a switchblade with a blade two or more inches long. For minors, the larger practical issue is often school or campus possession under Pen. Code § 626.10 rather than a general age-based ownership statute for ordinary knives. (Legislative Information)
No general statewide knife-law preemption statute was identified in the California codes reviewed for this article. (American Legal Publishing)
That cautious conclusion matters because official local codes still impose their own knife rules in at least some California jurisdictions. In other words, statewide legality does not automatically end the analysis in California. (American Legal Publishing)
Yes, local ordinances matter in California. (American Legal Publishing)
Los Angeles Municipal Code § 55.10 bars carrying in plain view certain knives or daggers in public places, using a three-inch threshold for knives, dirks, and daggers in that section’s definition. Los Angeles County Chapter 13.62 similarly prohibits carrying covered knives and daggers in plain view in unincorporated county areas, while preserving exemptions for lawful work, recreation, and recognized religious practice. San Francisco Police Code § 1291 takes a different approach: it treats several knives as dangerous weapons for purposes of loitering, rough conduct, and related behavior while armed. (American Legal Publishing)
Federal law is separate from California law and still matters in interstate commerce, federal jurisdictions, and mailing. (GovInfo)
The Federal Switchblade Act, 15 U.S.C. §§ 1241-1245, regulates switchblade knives in interstate commerce, provides exceptions, and separately addresses ballistic knives. Mailing rules also matter under 18 U.S.C. § 1716, which treats certain injurious articles as nonmailable and separately addresses ballistic knives. So a knife that is lawful under California state law can still raise separate federal issues if it is imported, shipped across state lines, mailed, or possessed in a federally regulated context. (GovInfo)
The table below summarizes the California statutes discussed in this article, including Pen. Code §§ 16470, 171.5, 171b, 171c, 20200, 20310, 20410, 20510, 20610, 20810, 21110, 21310, 21510, and 626.10. (Legislative Information)
| Issue | Practical statewide rule |
|---|---|
| Ordinary folding knives | Generally lawful to own. Closed folding knives are much safer under concealed-carry rules because a folding knife ordinarily becomes a dirk or dagger only when exposed and locked. |
| Fixed-blade knives | Generally lawful to own, but concealed carry is the main risk. California expressly says a knife openly worn in a sheath suspended from the waist is not concealed. |
| Concealed carry | Concealed carry of a dirk or dagger is generally illegal under state law. |
| Switchblades / automatics | The statewide switchblade definition and offense apply to blades two inches or more. Carry on the person, public passenger-area vehicle possession, and sale or transfer are prohibited. |
| Ballistic knives | Broadly prohibited to manufacture, import, sell, give, lend, or possess. |
| Disguised knives | Air gauge knives, belt buckle knives, cane swords, and lipstick case knives are prohibited categories. |
| Schools and campuses | K-12 schools and higher-education campuses have strict knife restrictions, including 2.5-inch thresholds in some settings. |
| Public buildings and airports | Knives over four inches are restricted in certain state or local public buildings, open public meetings, Capitol-related locations, and airport sterile areas. |
| Local ordinances | Still important. Los Angeles, Los Angeles County, and San Francisco each have local knife rules beyond the statewide code. |
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The main recent enacted change identified in the official materials reviewed for this article was SB 2 from the 2023-2024 session, Chapter 249, effective January 1, 2024. As relevant here, the current versions of Pen. Code §§ 171b and 171.5 are in force as of March 2026 and continue to restrict certain knives over four inches in public-building and airport-related settings. (Legislative Information)
By contrast, the core statewide knife sections reviewed for ownership and carry rules show older amendment dates, mostly from the 2010 recodification period and 2012 cleanup amendments. No separate later enacted change to those main statewide knife sections was identified on the current section histories reviewed through March 2026. (Legislative Information)
California does not specifically ban butterfly or balisong knives by name in the statewide statutes reviewed, but if the knife is carried in a way that makes it a dirk or dagger, concealed carry becomes the main statewide issue. (Legislative Information)
Under the statewide definition in Pen. Code § 17235 and the offense in Pen. Code § 21510, California’s switchblade rules apply to automatic knives with blades two inches or more in length. (Legislative Information)
That can create concealed-carry risk if the knife qualifies as a dirk or dagger. California’s express statutory safe harbor is a knife openly carried in a sheath suspended from the waist. (Legislative Information)
Often no, at least not the categories listed in Pen. Code § 626.10(b), which covers dirks, daggers, ice picks, and fixed blades longer than 2.5 inches, subject to specific exceptions. (Legislative Information)
Yes. Los Angeles city and Los Angeles County both have local plain-view knife ordinances that can be stricter than the statewide baseline. (American Legal Publishing)
No general statewide knife-law preemption provision was identified in the California codes reviewed, which is why local ordinances still need to be checked. (American Legal Publishing)
Warning: laws can change, local rules may still apply, and restricted places, intent, and personal status can affect whether knife possession or carry is lawful.
California state sources
Official local code sources
Federal sources