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TSA Rules for Multitools in 2026: What Actually Flies

There is a specific sound a checkpoint makes when it decides your week. The belt stops. The bin rolls backwards. And then a sentence that is shaped like a question but isn't one: is this your bag, sir.

Here is the part almost nobody knows. The TSA does not confiscate anything. Its officers have no authority to take an item off you — their own spokespeople are careful about this in interviews. What actually happens is that you surrender it. You hand over the multitool you have carried for six years, and you do it voluntarily, because the alternative is not getting on the plane.

Then it goes into a bin, and eventually onto a state surplus auction site, where somebody buys a lot of forty surrendered multitools for the price of one of them.

I have spent ten years designing tools that live in a wallet, which means I have spent ten years reading emails from people written about four minutes after that sentence. So this is not a rules summary copied off a government page. This is what the rule says, what the rule doesn't say, and where the gap between the two eats your gear.

01The entire rule is about sixty words long

TSA publishes a page for multi-tools. Read in full, it takes fifteen seconds, and it contains three facts:

Knives are out. All of them. The wording is "Multi-tools (multipurpose tools) with knives of any length are prohibited." Not knives over two inches. Not locking knives. Any length. A one-inch blade and a machete are the same object to this rule.

Scissors under four inches are in. Measured from the pivot, not overall.

Everything else is a tool, and tools have a size limit. TSA's separate tools page sets the ceiling at seven inches, measured end to end when assembled. Screwdrivers, wrenches, pliers — under seven inches they may be allowed in the cabin, over seven and they go in checked baggage.

And then, at the bottom of nearly every page TSA publishes, the sentence that overrides all of the above: the final decision belongs to the officer at the checkpoint.

That last line is not fine print. It is the actual operating system. The written rule tells you what is legal to attempt — the officer tells you what happens.

02Blade-free is a design decision, not a boarding pass

The gap between "my tool complies" and "my tool cleared" is an X-ray image. The machine does not read your spec sheet. It reads shapes, and an officer with three seconds per bag reads them faster than you can explain them.

Four shapes get gear pulled even when the rulebook is on your side.

Saw teeth. A saw insert is not a knife. On an X-ray, a row of teeth is a serrated cutting edge, and that is exactly what gets flagged. If your multitool takes modular inserts and one of them is a saw, that insert is checked-bag cargo. So is any serrated edge, on any card, for the same reason.

Points. An awl, a scribe, a piercing compass point. All legal by category, all shaped like the thing everyone is looking for.

Hidden layers. The nail-file slot that also holds a blade. The insert nobody opened since it was installed. If you cannot name every part of your tool in one breath, your bag is more likely to come off the belt — and the officer's job in that moment is to assume the least convenient interpretation.

Recessed cutters. This is the grey zone, and I am not going to pretend otherwise, because I build them. A cord cutter is a cutting edge set inside a slot — it slices paracord and zip ties, and there is no exposed edge to touch. It is not a knife by any definition TSA publishes. It is also not a shape most officers see forty times a day. We have flown with our Extreme and filmed it. That is evidence, not a guarantee, and anyone selling you a guarantee here is selling you something they do not own.

The workable posture at the checkpoint: pull the tool out of your wallet and put it in the bin where it can be seen clearly. Screeners spend less time on things they can see. Do not argue the regulation. You will be right, and you will be right on the wrong side of the belt.

03The seven-inch rule is the one you will never come near

SCALE · 7 in LIMIT

The rule you will never come near

TSA limitcarry-on tool 177.8 mm7.00 in

Carddiagonal 100.7 mm3.97 in

MRF cardlength 85.0 mm3.35 in

EU / UKblade or shaft 60 mm2.36 in

92.8 mm never used

0 40 80 120 160 mm

Seven inches is 177.8 mm. A credit card is 85 mm long, 54 mm wide, and 100.7 mm corner to corner. The limit is 2.09 times the longest dimension of the card. Even measured diagonally, a card sits at 57% of the ceiling.

Which means the size rule, the one that fills half the internet's TSA advice, is irrelevant to a wallet tool. I could design a card twice as large and still clear the limit. I don't, because the constraint that matters is a card slot, not a federal regulation.

Everything that decides whether a card flies happens at the edges. That is the whole reason the geometry of the Universal 4.0 is what it is: the cutting function lives on a removable insert instead of being milled into the body. Not because a removable blade is a better blade. It isn't, slightly. Because a blade you can take out is a card that flies, and a blade you can't take out is a card that flies in the hold.

04Which cards fly and which ones ride in the hold

X-RAY · WHAT GETS PULLED

Four shapes decide it, not the brand

Milled blade CHECKED

A cutting edge machined into the body. No way to remove it, no discussion at the belt.

Serration CHECKED

Reads as a serrated edge on X-ray every time, whatever it is called on the packaging.

Saw insert CHECKED

Saw teeth are a cutting geometry. Removable or not, in the card it goes to the hold.

Recessed cutter GREY ZONE

Compliant by definition, unfamiliar by shape. The final call belongs to the checkpoint — and if asked, call it what it is, a recessed cord cutter; never volunteer the word blade.

EVERY OTHER CUT-OUT FLIES wrenches, rulers, drivers, gauges, openers, protractors

The line is not brand loyalty and it is not price. It is whether a cutting edge is machined into the body of the card.

The OfficeWorker was designed backwards from this exact problem: 40+ functions, 2 mm thick, about 30 g in titanium, and zero blade elements anywhere in the geometry. No knife, no serration, no point. It cuts thread and strapping with a recessed slot. It is the card I hand to people who fly weekly and have already lost something at a checkpoint, which in my inbox is most people who fly weekly.

The Professional clears for the same structural reason — its box opener cuts tape from inside a recess — and it happens to be a drill gauge and a protractor, which is a strange combination to bring to an airport and a very good one to have on a job site three time zones from your toolbox. The Extreme carries a full 6–17 mm wrench set, spoke keys in 13/14/15 gauge, and a torque handle, and still has no knife on it.

The Universal 3.0 does not fly. It has a hardened cutting edge milled into the card, and I am not going to soften that in a blog post so you can find out at 5 a.m. in Denver. It is the better card for a truck and the wrong card for a carry-on. The 3.0 versus 4.0 versus 5.0 breakdown covers which generation belongs in which life.

See every cutout in 3D → Tool Explorer

05Europe is stricter, and Britain is where Americans get caught

Clearing a US checkpoint tells you nothing about the next one. On a multi-leg itinerary, the rule that governs your packing is the strictest checkpoint on the route, not the first.

The EU standard, Regulation 2015/1998, bans tools with a blade or a shaft longer than 6 cm from the cabin. The UK publishes something blunter. On gov.uk's own work-tools table, screwdriver, pliers, wrench, drill and hammer are all marked not allowed in hand luggage — with no length qualifier attached. A four-inch screwdriver that walks through Atlanta unremarked is, on paper, checked baggage at Heathrow.

Now the uncomfortable part about a flat card in Europe, since this is where every competitor's blog post goes vague. A card has no blade and no shaft. It is a 2 mm rectangle, and it appears on nobody's prohibited list under any category — which means the officer's discretion is not a footnote there, it is the entire procedure. Blade-free cards travel through European checkpoints constantly. That is a pattern, not a promise, and the 6 cm number gives you no protection you can point at, because there is nothing on the card to measure.

And the checkpoint is only half of Europe: what you may carry once you walk out of the airport — an edge in London, Berlin or Paris — runs on a different rulebook, which Where Your Card Is Legal goes through country by country.

I can add my own folder to that pattern. Between 2018 and 2019 I flew out of Ukraine with my prototypes, and back through checkpoints in France and Turkey. The cards rode inside the wallet, and the wallet went through the scanner the way wallets do — I did not even take them out into the bin. Among them was an early card with a machined edge, which is exactly the thing I told you three sections ago belongs in the hold.

Nobody stopped them. Notice that this is the opposite of the advice I gave above — the cards stayed in the wallet, invisible, and cleared as part of the noise. That is precisely the point: a 2 mm flat plate does not read as a threat on a screen. But a handful of checkpoints tells you about a handful of officers on a handful of mornings, and nothing about yours. My photos are a data point, not an exemption — and I pack my own cards today the way this article says to. The wallet trick is also aging out on its own: modern CT scanners flag density profiles inside a bag automatically, so treat every checkpoint as a direct read of raw geometry, not of visual noise. (One physical footnote: denser steel draws a bolder silhouette on the operator’s screen than titanium does.)

06Five minutes at home beats five minutes at the belt

PREFLIGHT · FIVE MINUTES

Decide it at home, not at the belt

01 Pull the insert Cut Tool out, onto the table — at home, not in the line.

02 Name every part Every function, in one breath. If you hesitate, the bag opens.

03 Saw · point · serration All three ride in the hold. No exceptions worth arguing.

04 Every leg, not the trip Pack for the strictest checkpoint on the route — not the first one. THE ONE PEOPLE SKIP

05 Card in the bin Flat, face up, visible. Seen beats explained.

The failure mode is almost never defiance. It is a person who packed at midnight and forgot which insert was in the card. Every one of these five steps exists to move a decision out of the line and into your kitchen, where it costs nothing and where nobody is standing behind you with a boarding pass and an opinion.

Step 4 is the one people skip. Your gear does not clear a trip. It clears each checkpoint on the trip, one at a time, and the last one gets the same vote as the first.

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Blade-free is not a compromise. It is a design constraint, and constraints are where the interesting engineering lives: forty functions with no cutting edge is a harder problem than sixty with one, and it is the reason the OfficeWorker exists at all.

Not sure which card matches how you actually travel — carry-on only, checked bag every time, or one of each in two different wallets? The Card Finder sorts it in four questions and about thirty seconds.

Andrii Gurskyi, founder & engineer, MRF.Tools

CATALOG · BLADE-FREE FILTER See all blade-free cards →