Can I Bring a Pocket Knife on a Plane?

Key restrictions

No knives in carry-on, regardless of blade length — even a 1-inch folding blade is prohibited.

Multitools with any blade are also banned from carry-on; bladeless multitools are allowed.

Allowed in checked baggage when sheathed or wrapped so handlers can't be injured.

A knife found at the checkpoint is surrendered, mailed home at your cost, or you exit security to re-pack it.

Why this matters

Pocket knives are the classic "I forgot it was in my bag" checkpoint item. Everyday-carry knives live in pockets, backpacks, and keychains, which is exactly how thousands of them end up surrendered at security every week. Unlike liquids, there is no small-size allowance: US rules prohibit every knife from carry-on, down to the tiniest keychain blade.

The rule is also stricter than many travelers remember. TSA briefly proposed allowing small blades in 2013 and reversed course — since then the ban has been total.

Restrictions

Carry-on: no knives at all. This covers folding knives, fixed blades, box cutters, razor-type blades, and any multitool that includes a blade. Only butter knives that are plastic or round-bladed pass.
Checked baggage: pocket knives are allowed, but they should be sheathed, folded and secured, or wrapped so a baggage inspector reaching into the bag cannot be cut.
International variations: some countries are stricter on arrival — flick knives and gravity knives are outright illegal to possess in the UK, Germany, Japan, and elsewhere, even in checked luggage. Japan's blade length laws can make carrying a pocket knife in public an offence.

What the official guidance says

TSA's knife entry is unambiguous: carry-on no, checked yes, except for plastic or round-bladed butter knives. TSA asks that any sharp object in checked bags be sheathed or securely wrapped to prevent injury to inspectors and handlers. The final decision on any item always rests with the officer at the checkpoint.

Frequently asked questions

What is the blade length limit for carry-on knives?

There is none — all knives are prohibited in US carry-on baggage whatever the length. The only exceptions TSA makes are plastic or round-bladed butter knives.

Are Swiss Army knives and multitools allowed in carry-on?

Not if they contain a blade, which almost all do. Multitools with only pliers, screwdrivers, and scissors under 4 inches are allowed; anything with a knife blade must go in checked baggage.

What happens if TSA finds a pocket knife in my bag?

You'll be offered the usual options: surrender it, take it back to a checked bag or your car, or mail it home where that service exists. Forgotten knives are one of the most common checkpoint surrenders, and in some airports can also mean a civil penalty.