TSA Liquid Rules for Travel — 3-1-1 Explained (2026)

TSA's 3-1-1 rule caps each carry-on liquid container at 3.4 oz (100 mL), fitting in one quart-sized clear bag, one per traveler. Gels, aerosols, pastes, creams, and any spreadable food (peanut butter, hummus, yogurt) count as liquids. Medications, baby formula, breast milk, and duty-free purchases are exempt but require declaration at screening. This guide covers the exact rule, every exception, what actually gets enforced versus what technically applies, and how international rules differ.

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The 3-1-1 Rule Explained

3-1-1 stands for three limits: 3.4 oz per container, 1 quart-size bag, 1 bag per traveler. All liquids in your carry-on must fit inside a single transparent quart-size (~7 x 8 inch) resealable bag. Containers larger than 3.4 oz are prohibited even if partially empty — TSA measures the container's marked capacity, not the volume of liquid inside. The bag must come out of your carry-on for screening; you place it in a separate bin at the checkpoint.

3.4 oz (100 mL) max per container
One quart-size clear resealable bag
One bag per traveler
Container capacity counts, not fill level
Bag comes out at screening — separate bin

What Counts as a Liquid

TSA's definition of 'liquid' includes anything that could be considered a liquid, gel, aerosol, paste, or cream. That includes obvious items (water, shampoo, sunscreen, perfume) and less obvious ones (peanut butter, hummus, cream cheese, yogurt, mascara, deodorant sticks that are gel-based, hair gel). Solid deodorant sticks, bar soap, and stick lip balm are NOT liquids and don't count. Powders are technically solids but international regulations and some TSA agents flag containers over 12 oz for extra screening.

Liquids, gels, aerosols, pastes, creams all count
Peanut butter, hummus, yogurt, cream cheese are liquids
Solid deodorant, bar soap, stick lip balm are NOT liquids
Gel deodorants and hair gels count as liquids
Powders over 12 oz get extra screening (not banned)

Medical Exceptions (Prescription and Over-the-Counter)

Prescription and over-the-counter liquid medications are exempt from the 3-1-1 rule in any quantity 'reasonable for the trip.' Declare them to the officer at the checkpoint and place them in a separate bin. They don't need to fit in your quart bag and don't need to be in original bottles, but original labeled containers speed screening. Contact lens solution, saline, and prescribed liquid medicine all qualify. TSA may test medically-necessary liquids for explosive residue.

Prescription liquids exempt in any 'reasonable' quantity
OTC medications (contact solution, saline) also exempt
Declare at checkpoint and use a separate bin
Original labels aren't required but speed screening
May be tested for explosive residue

Baby Formula, Breast Milk, and Baby Food

Formula, breast milk, and baby food in any quantity are allowed in carry-on regardless of the 3-1-1 rule — even without the child present. Declare at screening and place in a separate bin. Ice packs and cold packs to keep milk cold are also allowed even if fully frozen. TSA may screen liquids using a bottle scanner or ask a parent to open the container for visual inspection; refusing the visual inspection may mean the liquid isn't cleared, but TSA cannot force you to open it.

Formula, breast milk, baby food exempt in any quantity
Allowed even without the child present
Ice/cold packs also allowed, even fully frozen
Declare at checkpoint, place in a separate bin
Bottle scanner or visual inspection may be used

Duty-Free Liquids and STEBs

Duty-free liquids purchased at an airport are allowed through domestic connections if sealed in a Security Tamper-Evident Bag (STEB) with the receipt visible. The STEB seal must be intact and the purchase date must be within 48 hours. International-to-domestic connections in the US often require re-screening of duty-free liquids — the STEB helps but doesn't guarantee they clear. If in doubt, put the liquor bottle in your checked bag on the connecting flight to avoid loss.

Duty-free liquids in STEB bags with receipt are allowed
Seal must be intact; purchase within 48 hours
International-to-domestic US connections often re-screen
Bottle in checked bag is the safe option on connections

International Rules Are Very Similar (But Enforced Differently)

The EU, UK, Canada, Australia, and most of Asia use the same 100 mL / quart-bag structure as TSA, so a rule-compliant US carry-on clears international security too. Enforcement varies: London Heathrow and Amsterdam Schiphol are stricter than most US airports; Bangkok and Dubai are often more lenient. The UK is phasing in new CT scanners that will eventually allow 2L liquid containers and leave-in-bag screening at select airports — the rule change is airport-by-airport, not UK-wide. Always follow the 100 mL / quart-bag rule until you're at a confirmed CT-scanner airport.

EU/UK/Canada/Australia use same 100 mL / quart-bag rule
Heathrow and Schiphol enforce strictly
Bangkok and Dubai often more lenient
UK/EU CT scanners are rolling out — airport-by-airport

What TSA Agents Actually Enforce

TSA agents enforce the 3.4 oz limit strictly on gels and clear liquids in bottles (they can see them in the scanner) but often let solid-looking items pass (deodorant sticks, some pastes, small toothpaste tubes). The '1 quart bag' rule is enforced loosely — a slightly-oversized zipper bag or a rigid Ziploc pouch usually clears if the contents fit. What agents CAN'T do is force you to give up an item; they can only refuse to let it through, at which point you decide to check it, mail it, or discard it.

3.4 oz enforced strictly on clear liquids
Solid-looking items (stick deodorant, small toothpaste) often pass
'1 quart bag' enforced loosely if contents fit
You can always discard, check, or mail rather than give up the item

Frequently Asked Questions

What is the TSA 3-1-1 rule for liquids?

3-1-1 means: 3.4 oz (100 mL) per container, 1 quart-size clear resealable bag, 1 bag per traveler. All liquids, gels, aerosols, pastes, and creams in your carry-on must fit in that single quart bag. The bag comes out of your carry-on at security and goes in a separate bin.

Can I bring my own quart bag or does it have to be TSA-approved?

Any clear resealable ~7 x 8 inch bag works — a standard household Ziploc quart bag is fine. There is no official 'TSA-approved' certification. Reusable clear quart pouches (Peak Design, Bagsmart, or generic Amazon versions) also work. The bag must be transparent enough that TSA can see the contents through it.

Are medications subject to the 3-1-1 rule?

No — prescription and over-the-counter liquid medications are exempt in any 'reasonable' quantity for your trip. Declare them at the checkpoint and place in a separate bin. Contact lens solution, saline, and liquid prescriptions all qualify. Original labeled containers speed the process but aren't required.

What about baby formula, breast milk, and baby food?

All exempt in any quantity, even without the child present. Ice packs to keep them cold are also allowed. Declare at the checkpoint and use a separate bin. TSA may use a bottle scanner or ask for a visual inspection.

Are food items considered liquids?

Spreadable foods (peanut butter, hummus, yogurt, cream cheese, jam) count as liquids and must fit the 3-1-1 rule. Solid foods (cheese, bread, chocolate, crackers, snack bars) don't. Sauces, dips, and dressings are liquids. When in doubt, treat it as a liquid.

Do international airports use the same liquid rules?

Most do — EU, UK, Canada, Australia, and most of Asia use the same 100 mL / quart-bag structure. Enforcement varies by airport. The UK is rolling out CT scanners at select airports that will eventually allow 2L liquid containers and leave-in-bag screening, but the change is airport-by-airport. Assume 100 mL is the rule until you're at a confirmed CT-scanner checkpoint.

What happens if I bring a bottle over 3.4 oz?

TSA will pull the bottle out at screening and give you three options: discard it, return to check it, or (rarely) mail it. Agents cannot confiscate personal property beyond refusing to let it through security. Most travelers discard rather than lose their spot in line.

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