The 3.4-ounce limit for carry-on bags
You can bring a single container of liquid, gel, or aerosol through TSA security in your carry-on bag only if it holds 3.4 fluid ounces (100 milliliters) or less. This is the maximum size for any one container. If a container is larger than 3.4 ounces, you cannot bring it in your carry-on, even if it is not completely full.
The rule applies to anything that flows, spreads, or sprays: shampoo, conditioner, lotion, toothpaste, deodorant, sunscreen, peanut butter, yogurt, jam, honey, and liquid medications. Solid items like bars of soap, solid deodorant sticks, or chapstick are not restricted by this rule.
TSA officers at the checkpoint will measure containers by their labeled capacity, not by how much liquid is actually inside. A half-empty 5-ounce bottle of shampoo will be stopped because the container itself is larger than 3.4 ounces.
Key Takeaways
- Each liquid container in your carry-on must be 3.4 fluid ounces or smaller; the container size matters, not how full it is.
- All containers must fit inside a single clear quart-sized plastic bag, and you remove this bag at security to be screened separately.
- Larger containers of any liquid can go in your checked baggage with no size limit, as long as they follow hazmat rules.
- Some items like frozen gel packs, ice, and certain medications have different rules and should be checked before you pack.
- Duty-free liquids purchased after security can be brought on the plane if they are in a sealed bag with a receipt dated the same day.
The quart-sized bag requirement
All your liquid containers must fit together inside one clear quart-sized plastic bag. A quart bag is roughly 7 inches by 8 inches. You do not need to buy a special TSA-approved bag—any clear plastic bag of that size works, including a freezer bag from your kitchen.
At the checkpoint, you remove this bag from your carry-on and place it in the bin for X-ray screening. It goes through the scanner separately from your other belongings. After screening, you put it back in your carry-on or keep it in your personal item.
If your liquids do not fit in the bag, or if any single container exceeds 3.4 ounces, TSA will not allow those items through security. You will have to throw them away, mail them ahead, or check them in your baggage instead.
What you can pack in checked baggage instead
Checked baggage has no size limit for liquids, gels, or aerosols. You can pack full-sized bottles of shampoo, lotion, cologne, or any other liquid in your checked bag without restriction. However, some liquids are classified as hazardous materials and have additional rules even in checked baggage.
Flammable items like lighter fluid, paint thinner, and some nail polish removers are prohibited in both carry-on and checked bags. Aerosol cans with flammable propellant are also banned. Check the TSA website or call your airline before packing anything you are unsure about, because rules vary slightly by carrier.
If you are traveling with a large quantity of a common item like shampoo or lotion, checked baggage is your best option. You avoid the 3.4-ounce limit entirely and do not have to repack into travel-sized containers.
Medications, baby formula, and special exceptions
Liquid medications in reasonable quantities do not have to follow the 3.4-ounce rule, but you should declare them to TSA officers at the checkpoint. Bring the medication in its original labeled container with your name on it. Insulin, for example, can be brought in any size container.
Baby formula, breast milk, and baby food are also exempt from the 3.4-ounce limit. You can bring as much as you need for your flight. Again, declare these items when you reach security so officers know what they are screening.
Gel ice packs and frozen items are allowed in carry-on bags only if they are completely frozen solid at the checkpoint. If they have any liquid or slushy texture, they count as liquids and must follow the 3.4-ounce rule. Many travelers freeze gel packs the night before travel to may support they stay solid through security.
Duty-free liquids and the sealed-bag rule
You can bring liquids purchased at a duty-free shop after you pass through security, even if the bottles are larger than 3.4 ounces. The items must be in a sealed transparent bag with a receipt dated the same day. This rule applies to alcohol, perfume, cologne, and other liquids sold in airport shops.
The sealed bag protects the liquid from being opened and consumed before you board. If the bag is opened or the receipt is missing, TSA may not allow the items on the plane. Keep your receipt and do not open the bag until you are on the aircraft or at your destination.
This exception only works for purchases made after you pass through security at your departure airport. Liquids you buy at a regular store before arriving at the airport must still follow the 3.4-ounce carry-on rule.
Common mistakes and what happens at security
The most common mistake is packing a container larger than 3.4 ounces, even partially full. TSA measures by container size, not contents. A 5-ounce bottle of lotion that is only one-quarter full will still be confiscated.
Another frequent error is forgetting to remove the liquid bag from your carry-on before reaching the X-ray machine. This slows down the line and may trigger additional screening. Have your bag ready and accessible so you can remove it quickly.
Travelers also sometimes pack liquids in checked bags without realizing they are hazardous. Certain aerosols, adhesives, and cleaning products are banned from checked baggage. If you are unsure whether something is allowed, check the TSA website or contact your airline before you pack.
International flights and other countries' rules
The 3.4-ounce rule applies to flights departing from the United States. If you are connecting through a U.S. airport on an international flight, the rule still applies to your carry-on at the first checkpoint.
Other countries have their own liquid rules. The European Union, for example, uses the same 3.4-ounce limit, but some countries have stricter rules. Research your destination country's regulations before you pack. Your airline's website usually has this information, or you can contact the airport directly.
If you are flying out of the United States to another country and then to a third country, you may be able to bring duty-free liquids on the second flight if they are in a sealed bag with a receipt. Rules vary by country and airline, so confirm before you travel.
Frequently Asked Questions
What happens if I accidentally bring a container larger than 3.4 ounces to security?
TSA will not allow it through the checkpoint. You will have to throw it away, mail it to your destination, or check it in your baggage if you have time. There is no fine, but you will lose the item. To avoid this, measure or weigh your containers before you pack.
Can I bring an empty container larger than 3.4 ounces?
Yes. Empty containers are not subject to the liquid rule because they contain no liquid. However, if a container is labeled as holding more than 3.4 ounces, TSA may question whether it is truly empty and may not allow it. To be safe, bring containers that are clearly empty or smaller than 3.4 ounces.
Do solid deodorants and chapstick count as liquids?
No. Solid deodorant sticks, chapstick, and other solid items are not restricted by the 3.4-ounce rule. Only items that flow, spread, or spray are considered liquids. Solid products can be any size and do not need to go in the quart bag.
Can I bring a full-sized bottle of water through security?
No. Water is a liquid and must follow the 3.4-ounce rule in carry-on bags. You can bring an empty water bottle through security and fill it at a water fountain or bottle-filling station after you pass the checkpoint. Many airports have these stations near the gates.
Are there any liquids that are completely banned from planes?
Yes. Flammable liquids like lighter fluid, paint thinner, and some nail polish removers are banned from both carry-on and checked baggage. Certain adhesives, pesticides, and other hazardous materials are also prohibited. Check the TSA website for a complete list before you pack anything unusual.