No. TSA prohibits knives of every type and blade length in carry-on bags, including folding pocket knives, multi-tools with a blade, and plastic-handled kitchen knives. Almost all knives are allowed in checked baggage when the blade is sheathed or securely wrapped. The only carry-on exceptions are round-bladed plastic or metal butter knives.
There is no minimum blade length that makes a knife acceptable in a carry-on. Officers apply the ban to the shape and function of the tool, not its size, so a one-inch keychain blade is refused for the same reason a chef knife is.
| Knife type | Carry-on | Checked |
|---|---|---|
| Pocket knife (any blade length) | Not allowed | Allowed, sheathed |
| Swiss Army knife / multi-tool with blade | Not allowed | Allowed, sheathed |
| Kitchen or chef knife | Not allowed | Allowed, wrapped |
| Hunting or fixed-blade knife | Not allowed | Allowed, sheathed |
| Box cutter / utility knife | Not allowed | Allowed, blade retracted |
| Corkscrew with foil blade | Not allowed | Allowed |
| Corkscrew without a blade | Allowed | Allowed |
| Sword, saber, machete | Not allowed | Allowed, sheathed |
| Plastic or round-bladed butter knife | Allowed | Allowed |
| Scissors under 4 inches from the pivot | Allowed | Allowed |
| Scissors over 4 inches from the pivot | Not allowed | Allowed |
| Safety razor with the blade installed | Not allowed | Allowed |
| Straight razor | Not allowed | Allowed |
Between 2005 and 2013 TSA allowed small blades under four centimeters, and in 2013 the agency proposed reinstating that allowance. The proposal was withdrawn after opposition from flight attendant unions and airlines, and the total ban has been in force since. Advice you may still find online about "blades under 2.36 inches" reflects the withdrawn rule, not current screening.
The four-inch measurement that does exist applies only to scissors, and it is measured from the pivot point to the tip rather than the overall length of the tool.
Nearly every civil aviation authority bans knives in the cabin, so a checked knife stays checked for the whole itinerary. The trap is a self-transfer connection where you claim your bag and re-check it, which puts you through security again in a country that may treat the knife as an illegal weapon rather than a prohibited carry-on item.
If you bought a knife duty-free after clearing security, it is still a knife on your next flight. Airside purchases are exempt from the liquid rules, not from the weapons rules, and staff will normally arrange to deliver a boxed blade to your destination gate instead.
No. TSA prohibits all knives in carry-on bags regardless of blade length or whether the blade folds. The only exceptions are plastic knives and round-bladed butter knives. Knives may be packed in checked baggage with the blade sheathed or wrapped.
None. There is no permitted blade length for carry-on bags. The rule allowing blades under four centimeters was rescinded in 2005 and a 2013 proposal to bring it back was withdrawn.
Yes. Pocket knives of any size are allowed in checked baggage when the blade is closed and the knife is sheathed or wrapped so it cannot injure a baggage handler.
No. Any multi-tool that includes a blade is prohibited in carry-on bags. Bladeless multi-tools with only pliers, screwdrivers, and bottle openers are generally permitted, though the officer at the checkpoint makes the final call.
The bag is searched and you are asked to surrender the knife, return it to your vehicle, or mail it if the airport offers that service. Surrendered knives are not returned, and repeat violations can cost you PreCheck eligibility.
Yes, in checked baggage. Hunting knives, fillet knives, and multi-tools all travel checked with the blade covered. Declare firearms separately at the airline counter; knives alone do not require a declaration.