Are butterfly knives illegal in California? A lawyer explains (2024)

Posted on September 11, 2023

Under Penal Code 21510 PC, butterfly knives are considered a form of a switchblade and are illegal in California. Specifically, it is a crime to carry, possess in public, sell, or otherwise transfer a butterfly knife.

Convictions are misdemeanor offenses that carry up to 6 months in jail.

Are butterfly knives illegal in California?

In California, butterfly knives are prohibited by Penal Code sections 21510 and 17235 PC.

Penal Code 21510 prohibits knowingly doing the following activities with a switchblade knife that has a blade length of 2 or more inches:

• possess the knife in the front of a motor vehicle in a public place, or in any place open to the public,
• carry the knife, or
• sell the knife, offer it for sale, or loans, transfers, or gives the knife away.¹

Law enforcement also has the burden of proving that you:

• knew that you had a switchblade on your person or in your vehicle, and
• knew that the knife had the characteristics of a switchblade.²

They do not have to prove that you intended to use the knife as a weapon – only that you had it.³

Penal Code 17235 PC defines what is meant by the phrase “switchblade knife.” These types of knives:

• look like pocketknives, and
• have one or more blades of 2 inches or longer, which can either be:
  • automatically released with a button, by applying pressure on the handle, with a flick of the wrist, or by some other mechanical device, or
  • released with the weight of the blade or by any other type of mechanism.⁴

However, these automatic knives are not considered switchblades if they have the following characteristics:

• a detent, catch, or other mechanism that provides resistance to the blade’s opening or that provides a bias towards the knife’s closure, and
• opens with one hand with either:
  • thumb pressure solely to the blade of the knife, or
  • a thumb stud attached to the blade.[5]

This exception covers box cutters.

According to a California appellate court, this definition of a switchblade includes butterfly knives because

• they can easily be opened with one hand and
• do not have a catch to prevent them from opening.⁶

Because a butterfly knife is a type of switchblade under Penal Code 17235 PC, they are prohibited by Penal Code 21510 PC.

What is a butterfly knife?

A butterfly knife is a type of pocketknife that can be folded to hide the blades. When in the closed position, the blades of the folding knife are concealed inside grooves in the handles. The handles are then held together with a latch. Once unlatched, the knife’s handles can be opened and the blade exposed with a flick of the wrist.

Butterfly knives are also known as:

• fan knives,
• balisong knives, or
• batanga knives.

The names reflect the knife’s origin in the Philippines.

What are the penalties of a conviction?

Possessing a butterfly knife is a misdemeanor in California. Convictions carry up to:

• 6 months in county jail, and/or
• $1,000 in fines.

However, many of these cases are punished with misdemeanor probation. Also known as summary probation, this would mean that you would not serve a jail sentence. Instead, the sentence would be served on community supervision. You would have to abide by the terms of your release. These often include terms like:

• performing community service,
• not committing another crime or getting arrested,
• going to counseling,
• electronic monitoring, and
• not contacting or associating with certain people.

Judges in California tend to impose jail time, rather than summary probation, if there are aggravating factors in the case. These factors can include:

• you have a criminal history, especially if you already had a prior conviction for possessing a butterfly knife or some other kind of knife,
• potential gang ties,
• a history of violence,
• a finding that you intended to use the knife as a weapon or to sell it to someone who was, and
• not cooperating with police.

Can a switchblade implicate other California knife laws?

A butterfly knife can also lead to other charges under California’s knife laws, including for:

• carrying a knife in a public building (Penal Code 171b PC),
• carrying it onto school grounds (Penal Code 626.10 PC),
• brandishing the butterfly knife (Penal Code 417 PC), and
• using the knife to commit an assault (Penal Code 245a1 PC).

Some of these offenses are very severe. Using a butterfly knife to commit an assault can be a felony offense, punishable with up to 4 years in state prison.

Is there a federal law that covers butterfly knives?

There is also a federal law that prohibits the possession of a switchblade. It also covers butterfly knives, as well.

This law makes it a crime to:

• introduce or transport a switchblade into interstate commerce,⁷ or
• possess a switchblade on federal or Indian lands, or on other property that is subject to federal jurisdiction.⁸

These areas that are subject to federal jurisdiction include:

• federal parks,
• military bases, and
• Indian reservations.

The only exception is for people who:

• are in the armed forces and who are acting in the performance of their duty, or
• only have one arm and the blade is less than 3 inches in length.⁹

The definition of “switchblade” under this law is broad enough to cover butterfly knives. To be a switchblade under the law, the knife has to open automatically through either:

• hand pressure to a button or some other device on the handle of the knife, or
• the operation of inertia, gravity, or both.¹⁰

The penalties of a conviction under the federal switchblade law are up to:

• $2,000 in fines, and/or
• 5 years in prison.

Are there local laws that regulate knife possession?

Certain cities and counties have their own regulations and ordinances regulating knife possession. When these rules conflict with California state law, courts have come to differing conclusions about which law gets applied.¹¹

For example, Los Angeles County has a local ordinance that forbids the open carry of any knife with a blade that is longer than 3 inches.¹² The City of Los Angeles also forbids the concealed carry of

• all dangerous or deadly weapons,
• including knives.¹³

The intersection of these laws can create confusion. The legal advice of a criminal defense lawyer can help to clear things up for people who want to carry knives for the purpose of self-defense.

What other knives are prohibited in California?

California knife laws regulate the possession and use of other knives, as well. State law creates 3 categories for these potentially deadly weapons:

1. knives that can be legally carried openly, but not concealed,
2. knives that can be carried openly or concealed without breaking the law, and
3. knives that are always illegal to carry.

Butterfly knives and switchblades belong in Category 3 – knives that are always considered to be prohibited weapons. In this category are also the following types of illegal knives:

• ballistic knives (Penal Code 21110 PC),
• belt buckle knives (Penal Code 20410 PC),
• spring-blade knives (Penal Code 21510 PC),
• spring-loaded knives (Penal Code 21510 PC),
• knives with telescoping or out-the-front (OTF) blade (Penal Code 21510 PC),
• gravity knives (Penal Code 21510 PC),
• writing pen knives (Penal Code 20910 PC),
• air gauge knives (Penal Code 20310 PC),
• cane swords (Penal Code 20510 PC), and
• undetectable knives, or those that will not trigger a metal detector (Penal Code 20810 PC).

California law also presumes that these knives are dangerous weapons.¹⁴

Category 2 is for folding knives that can be carried in the open or concealed, so long as they are folded or closed. It includes the following types of knives:

• pocket knives,
• swiss-army knives, and
• certain utility knives, like a snap-blade knife.¹⁵

Finally, Category 1 knives are for dirks and daggers. These are knives that are capable of ready use as a stabbing weapon and can inflict great bodily injury or death.¹⁶ They include the following weapons, tools, and utensils:

• bowie knives,
• chef’s knives and other fixed blade knives,
• daggers,
• stilettos,
• ice picks,
• razors with unguarded blades, and even
• knitting needles.

To carry knives listed in Category 1, California law requires an open carry. The concealed carry of any of these types of knives is a wobbler in California. Prosecutors can choose to pursue misdemeanor or felony charges. If pursued as a misdemeanor, a conviction carries up to:

• 1 year in county jail, and/or
• $1,000 in fines.¹⁷

If pursued as a felony, convictions carry up to:

• 3 years in prison, and/or
• $10,000 in fines.¹⁸

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