What does the TSA 3-1-1 rule actually mean?

The 3-1-1 rule means each liquid, gel, aerosol, cream, or paste in your carry-on must be in a container of 3.4 ounces (100 ml) or less, all containers must fit in 1 quart-size clear zip-top bag, and each traveler is allowed 1 bag. Anything larger gets confiscated — even if the container is not full.

Is it 3.4 oz or 100 ml — which is correct?

Both are correct. TSA rounds 100 ml up to 3.4 fluid ounces for U.S. labeling, but the actual legal limit is 100 ml. If your container says '100 ml' or '3.4 fl oz' and no more, you are compliant. A '3.5 oz' or '4 oz' bottle is not compliant even if it is only half-full.

What are the most commonly confiscated liquids at TSA?

The top items TSA confiscates are oversized water bottles, full-size shampoo, full-size sunscreen (especially for beach trips), peanut butter (yes, it counts as a liquid), yogurt, snow globes over 3.4 oz, hummus, honey, salsa, and opened perfume bottles over 100 ml. The rule covers anything you could pour, squeeze, spread, or spray.

Can I bring medication over 100 ml?

Yes. Prescription and over-the-counter liquid medications are exempt from the 3-1-1 rule in 'reasonable quantities' for the duration of your trip. Declare them at the checkpoint, keep them separate from your quart bag, and expect extra screening. The same exemption applies to breast milk, formula, juice for infants, and medically necessary gels.

Do CT scanners let me skip the quart bag in 2026?

At some U.S. airports, yes. TSA's new Analogic and Smiths Detection CT scanners can screen liquids without removal from the bag, and the agency has been quietly phasing out the quart-bag requirement at retrofitted lanes. But the 100 ml per container limit has not changed — only the packaging and removal requirement. Until full national rollout (expected 2028–2030), assume the full 3-1-1 rule applies.

Is the TSA rule the same in Europe, Asia, and the UK?

The 100 ml per-container standard is globally aligned, but quart-bag and scanning rules vary. UK airports with new CT scanners have lifted the 100 ml limit to 2 liters at some lanes, but reinstated restrictions at others in 2024 after scanner issues. The EU still enforces 100 ml. Asia varies by airport. Always check the departure airport's current rule the week before you fly, not the week before you booked.

Does the 3-1-1 rule apply to duty-free liquids?

No — liquids purchased at duty-free after security are allowed in any volume, as long as they are sealed in the tamper-evident STEB (Security Tamper-Evident Bag) with the receipt visible. The catch: if you have a connecting flight and need to re-clear security, the bag must remain sealed and you may be required to show the receipt. Opening the STEB voids the exemption.

Will TSA confiscate my snow globe?

Yes, if it contains more than 3.4 oz of liquid — and most snow globes do. TSA publishes snow globes as one of their top confiscated items around the holidays. Pack them in checked luggage, or ship them home. Same rule applies to decorative bottles, perfume gift sets, and jarred preserves over 100 ml.

Korean Air Carry-On Size: The 10 kg Rule That Catches People, Not the 55 cm

Korean Air carry-on and checked baggage size limits

Korean Air's carry-on size is 55 x 40 x 20 cm, or 115 cm when you add the three sides. Most people who get stopped are not stopped for that. They are stopped for the sentence underneath it: "Carry-on baggage weight: Not exceeding 10 kg in total." Ten kilograms, and the word that matters is total — the cabin bag and the personal item are weighed as one allowance.

The numbers, exactly as Korean Air prints them

What Korean Air publishes	Official figure
Carry-on (inches)	21.7 × 15.7 × 7.9 in (converted)
Carry-on (centimetres)	55 × 40 × 20 cm
Personal item (inches)	15.7 × 11.8 × 5.9 in (converted)
Personal item (centimetres)	40 × 30 × 15 cm
Carry-on weight limit	10 kg
Wheels and handles counted?	Yes
Checked bag: max weight	23 kg
Checked bag: max total size	158 cm

Where these numbers come from: Korean Air carry-on page, Korean Air checked bag page, Korean Air excess baggage page. Read and recorded on 2026-08-31. Every figure on this page is copied from those pages — nothing here is estimated. Airlines change baggage rules without notice, so check the official page before you fly.

Ten kilograms, counted across both bags

Read the two lines together and the reason people are surprised at the gate becomes obvious. Korean Air allows one carry-on bag plus one personal item, and then caps the combined weight at 10 kg for Economy and Premium. A 3 kg empty hard-shell case, a laptop, a camera and a coat can reach 10 kg without the case ever being full.

Ten kilograms is also stricter than every other airline on this page. Of the eight, only Korean Air and Frontier publish a cabin weight limit at all, and Frontier's is 35 lb — about 15.9 kg, more than half again as much. American, United, Delta, Southwest and JetBlue publish no cabin weight figure. Air Canada explicitly says there is none.

The size rule has its own trap for anyone connecting from a US carrier. Korean Air's depth limit is 20 cm. The bag sold across the United States as the standard carry-on is 9 inches deep, which is 22.86 cm — 2.86 cm over. Its height, 22 inches, is 55.88 cm against Korean Air's 55 cm limit, so that is over too. Curiously the same bag passes the total rule: its three sides add to 114.3 cm, inside the 115 cm ceiling. Korean Air's page gives the total and the per-side figures as alternatives, and the per-side figures are the restrictive ones.

Two exceptions on the same page are worth knowing. First and Prestige Class get two carry-on bags and 18 kg (40 lb) in total rather than 10 kg. And for codeshare flights, Korean Air warns that the operating airline's rules may apply instead of its own — a KE flight number does not guarantee a KE baggage policy.

Measuring your own bag against these numbers

The bag most retailers label "the standard carry-on" is 22 x 14 x 9 inches. Converted exactly, that is 55.88 x 35.56 x 22.86 cm, and the three sides add to 114.3 cm. Held against Korean Air's published limits, here is where it stands.

It does not fit — at least not on paper.

Longest side: the standard bag is 55.88 cm against a published limit of 55 cm — over by 0.88 cm.
Shortest side: the standard bag is 22.86 cm against a published limit of 20 cm — over by 2.86 cm.

This one is not a rounding artefact. Korean Air publishes its limits in centimetres first, and the shortfall is real enough that a rigid case will be visibly proud of a sizer. A soft bag at the same nominal size usually passes because it compresses; a hard shell often does not.

The reverse question matters just as much if you already own luggage. A bag bought to fit Southwest Airlines, Frontier Airlines, Air Canada, JetBlue, American Airlines, United Airlines, Delta Air Lines does not — those boxes are larger than Korean Air allows in at least one direction.

Whichever airline you are flying, measure the same way the airline does: bag packed, tape across the widest bulge rather than the frame, wheels and handle included, expansion zip closed. Every airline on this page that says anything about wheels says they count.

What Korean Air does not publish

These were checked against Korean Air's own baggage pages on 2026-08-31. The following are simply not stated there, so treat any number you find elsewhere for them as somebody's inference rather than a rule:

A carry-on weight limit in pounds
The carry-on size in inches
Personal item dimensions in inches
A personal item weight limit

Korean Air gives no inch conversion anywhere, which matters because most luggage sold in North America is specified in inches. The centimetre figures on this page are Korean Air's own.

How Korean Air compares with the other seven

Korean Air has the smallest cabin allowance by volume of the eight, and the only weight cap under 30 lb. Korean Air has the smallest published cabin box of the eight, at 44.0 litres — 18.9 litres behind Southwest Airlines at the top. Volume is the published box multiplied out, which is the fairest way to compare boxes of different shapes.

Airline	Carry-on (in)	Carry-on (cm)	Volume (L)	Weight cap	Personal item (in)
Delta Air Lines	22 × 14 × 9 in	56 × 35 × 23 cm	45.1	—	not published
Korean Air	21.7 × 15.7 × 7.9 in†	55 × 40 × 20 cm	44.0	10 kg	15.7 × 11.8 × 5.9 in

† converted from the figure the airline does publish. Southwest and Frontier publish inches only; Korean Air publishes centimetres only. Everything without a dagger is printed on the airline's own page in that unit.

The full eight-airline table, including checked bag limits, is on the comparison page. Alaska Airlines is deliberately absent from it: its baggage pages would not open to us, and we would rather leave a gap than print a figure we could not read on an official page.

Buying for Korean Air, and what to weigh before you leave

Size down. Korean Air's 20 cm depth rules out the standard American 9-inch case, so look for cases sold specifically as international carry-on at 55 x 40 x 20 cm — a widely available European size that Korean Air's figures match exactly.

Then weigh everything, including the personal item, before you leave home. Ten kilograms across both bags is the binding constraint for almost everyone, and it is far easier to fix on your bedroom floor than at a check-in counter. If you are flying Prestige or First, the allowance is two bags and 18 kg in total, which changes the calculation considerably.

The other seven airlines

Related pages on TripPack

All eight airlines in one table — carry-on, personal item and checked limits side by side.
Carry-on packing list — what to actually put in the bag once you know it fits.
How to measure a carry-on bag — where to hold the tape.
Baggage weight limits explained.

All figures on this page come from our airline baggage data table — official sources, quoted. The same figures are published as an open dataset under CC BY 4.0, with the source sentence and source URL kept against every number: JSON or CSV.