Liquids and batteries
TSA liquid rule: 3.4 ounces, one quart bag, and the exemptions
Pick the size printed on your bottle and how many you carry: the checker says whether it passes a US checkpoint or belongs in the checked bag.
Can I take this liquid through security?
101 ml per container
Not in carry-on: pack it in a checked bag
| Limit per container | 3.4 oz (100 ml) |
| Bag | quart-sized bag, one per passenger |
| Your containers | 4 × 101 ml |
Larger liquids go in checked bags. Medicines, baby formula, breast milk and baby food over 3.4 oz are allowed in carry-on and need not fit in the bag.
At every US airport the TSA applies one rule to liquids, aerosols, gels, creams and pastes in the carry-on: each container holds 3.4 ounces (100 ml) or less, and all of them fit in one quart-sized bag per passenger. That is the 3-1-1 rule: 3.4 ounces, 1 quart bag, 1 bag each. The figure that counts is the capacity printed on the container, so a half-empty 6 ounce bottle of shampoo is refused even if only two ounces are left inside. Larger bottles travel in the checked bag, where the TSA sets no size per container for ordinary toiletries. Three groups are exempt from the size limit and from the bag: medicines, baby formula and breast milk, and baby food; they may exceed 3.4 ounces in the carry-on and are declared to the officer for separate screening. The rule has not moved in 2026, unlike the UK, where several airports now accept containers up to 2 litres.
Is this container under the TSA 3.4 ounce limit?
In the carry-on quart bag?
Yes
| In milliliters | 101 ml |
| Limit | 3.4 oz (100 ml) |
The size printed on the container counts, not how full it is.
Sizes, fees and rules read by Radif Partners · Editorial policy · How we check
The 3-1-1 rule, item by item
Three numbers sum it up. Every container in the carry-on holds 3.4 ounces, which is 100 milliliters, or less. All those containers go into a single quart-sized bag, the clear resealable kind. Each passenger, children included, gets one such bag. The officer may ask you to take the bag out of the carry-on and place it in a bin, so pack it near the top. A bag that will not close is a bag with too much in it: something has to move to the checked bag or stay behind.
The rule covers far more than drinks. Anything you can pour, pump, squeeze, spread or spray counts as a liquid at the checkpoint: hair gel, mascara, liquid foundation, peanut butter, hummus, yogurt, honey, aerosol deodorant. Solid versions escape it. A bar of soap, a stick deodorant, solid shampoo, a lipstick or a powder foundation travel loose in the carry-on with no size limit.
| Item | Carry-on | Checked bag |
|---|---|---|
| Shampoo, conditioner, body wash | carry-on if 3.4 oz or less, in the quart bag | any size |
| Toothpaste, gel, cream, lotion, sunscreen | carry-on if 3.4 oz or less, in the quart bag | any size |
| Liquid medicine | exempt: any size, declared at screening | any size |
| Baby formula, breast milk, baby food | exempt: any size, declared at screening | any size |
| Drinking water and soft drinks | only if 3.4 oz or less; empty bottles are fine | any size |
| Spirits of 24% to 70% alcohol | only miniatures of 3.4 oz in the quart bag | up to 5 liters per passenger, unopened retail packaging |
The three exemptions, and how to use them
Medicines, baby formula and breast milk, and baby food are the only liquids the TSA lets through above 3.4 ounces in the cabin. They also stay out of the quart bag, which leaves its full space for toiletries. The exemption does not work silently: take these items out, put them in a separate bin and tell the officer what they are before the belt starts. They go through additional screening and the officer may open a container, which is why a pharmacy label or the original box saves time.
Everything else that is liquid has no exemption, however necessary it feels: a full-size hand cream bought for a long trip, a large sunscreen for the beach, a bottle of water filled before the line. Either it is transferred into containers of 3.4 ounces, or it is emptied, or it goes in the hold.
What goes in the checked bag instead
The checked bag is the outlet for everything larger: the full-size shampoo, the bottle of olive oil brought back from a trip, a jar of jam for a relative. For toiletries the TSA sets no per-container size in the hold. Alcohol is the exception that has numbers: up to 5 liters per passenger of drinks between 24% and 70% alcohol, in unopened retail packaging, and nothing above 70%. The food and drink page has a checker for bottles. Adding a checked bag to carry two bottles of wine costs money on most US airlines; the bag fee comparison gives the price of the first bag each way.
Can this bottle go in a checked bag?
In a checked bag
Allowed
| Rule that applies | 24–70%: 5 liters max, unopened retail packaging |
| Carry-on | only 3.4 oz bottles in the quart bag |
TSA rule; your airline and your destination’s customs allowance may be stricter.
Liquids bought after the checkpoint, in airport shops, are not counted: they were never screened against your carry-on. On a journey with a connection where you go through security again, as when you arrive from abroad and change planes in the US, the 3-1-1 rule applies afresh at that second checkpoint. The TSA liquids page describes how duty-free purchases are handled in that case; read it before buying a large bottle on the first leg.
Same trip, other rule: flying back from the UK
A round trip between the US and the UK no longer runs on a single liquids rule. The outbound leg follows the TSA everywhere. On the way back, it depends on the airport. Heathrow, Gatwick, Birmingham, Edinburgh, Bristol, Belfast International have published, on their own security pages, a limit of 2 litres per container with no plastic bag, because their new scanners see liquids inside the cabin bag. The other UK airports on this site keep 100 ml per container, though most of them no longer ask for the bag either. GOV.UK keeps 100 ml and a bag of about 1 litre as the general rule unless an airport says otherwise.
The trap runs in one direction: a 500 ml bottle of sun cream accepted at Heathrow or Gatwick on the way out of London is refused at a US checkpoint if you connect and are screened again, and at any of the 100 ml airports in the UK. Pack for the strictest checkpoint of the trip, which for most travelers is the US one.