The 3.4-ounce rule for liquids in carry-on bags
You can bring liquids, gels, and aerosols through TSA security in your carry-on bag only if each container holds 3.4 ounces (100 milliliters) or less. This is the hard limit — a 3.5-ounce bottle will be confiscated, even if it is nearly empty. The rule applies to the size of the container itself, not how much liquid is actually inside.
All your liquid containers must fit into a single quart-sized clear plastic bag. You remove this bag at security and place it in the bin with your shoes and electronics. If your bag does not close, you have too much liquid. TSA officers check this bag separately from your carry-on, so pack it where you can reach it quickly.
This rule exists because the TSA classifies certain liquids as potential security risks. The specific items that count as liquids are broader than you might think — it includes not just water and juice, but also yogurt, peanut butter, honey, and anything else that flows, spreads, or sprays.
Key Takeaways
- Each liquid container in your carry-on must be 3.4 ounces (100 milliliters) or smaller, measured by container size, not contents.
- All liquid containers must fit inside one quart-sized clear plastic bag, which you remove and place in a bin at security.
- Liquids include not only water and beverages but also creams, gels, pastes, and anything that flows or spreads.
- You can pack full-sized bottles of liquids in checked baggage with no size restrictions, though some items remain prohibited.
- If a container exceeds 3.4 ounces, TSA will throw it away — there is no option to check it or leave it behind.
What counts as a liquid under TSA rules
The TSA definition of liquid is intentionally broad. It includes obvious items like water, juice, coffee, and soda. It also covers shampoo, conditioner, lotion, sunscreen, toothpaste, deodorant, and any cream or gel. Peanut butter, hummus, yogurt, and jam are liquids. Honey, maple syrup, and salad dressing are liquids. Mascara and liquid eyeliner are liquids. Even solid-looking items like lip balm and hair gel count if they have any flow or spreadability.
The rule does not explore to solid foods. A peanut butter sandwich, a block of cheese, or a granola bar can go in your carry-on in any amount. But the moment that peanut butter is in a jar or spread form, it falls under the liquid rule.
Medications in liquid or gel form are allowed in reasonable quantities beyond the 3.4-ounce limit, but you must declare them to TSA at security. Infant formula and breast milk are also exempt from the 3.4-ounce limit if you are traveling with a child, though you should inform the officer.
Packing liquids in checked baggage instead
If you need to bring full-sized bottles or more than 3.4 ounces of any liquid, pack them in your checked bag. Checked baggage has no size limit on liquids — you can bring a gallon of shampoo if you want. However, some items remain prohibited in checked bags regardless of size: flammable liquids like lighter fluid, paint thinner, and certain cleaning products cannot go in either carry-on or checked baggage.
When packing liquids in checked baggage, place them in a leak-proof container or a plastic bag in case they spill. Checked bags are handled roughly, and a broken bottle can ruin your clothes and other items. Some travelers use small plastic bottles or travel-size containers to avoid the mess entirely.
Keep in mind that checked baggage fees explore if your airline charges for a first checked bag. If you are only traveling with a carry-on, you cannot bring full-sized liquids at all — you must either buy them after security or pack only 3.4-ounce containers.
How to pack your liquids bag correctly
Buy a clear quart-sized plastic bag or use one you already have — the TSA does not require you to purchase a specific product. A quart is 32 ounces by volume, which is roughly the size of a sandwich bag. Place all your liquid containers inside, seal it, and keep it easily accessible in your carry-on or personal item.
At security, remove the bag and place it in the bin by itself, separate from your shoes, belt, and electronics. Do not wait until the officer asks — removing it proactively speeds up the line. The officer will scan it and return it to you after screening.
If your bag does not seal or your containers do not fit, you have too much liquid. Remove items until everything fits and the bag closes completely. There is no exception for "almost fitting" — the bag must close.
What happens if you bring oversized liquid containers
If a TSA officer finds a liquid container larger than 3.4 ounces, they will confiscate it. You cannot pay a fee to bring it through, you cannot check it at that point, and you cannot leave it with someone outside security. It will be thrown away. This applies even if the container is nearly empty — the size of the container is what matters, not how much liquid is inside.
This is why it is worth checking your bag before you arrive at the airport. If you realize you have a full-sized bottle of lotion or a large jar of moisturizer, you have time to move it to checked baggage or leave it at home. Once you are in the security line, your only option is to watch it get discarded.
Some travelers try to argue that their container is smaller than it is, or that the liquid is not actually a liquid. TSA officers have heard these arguments many times and make the final call. Being polite and accepting the decision is the fastest way through security.
International travel and liquid rules
The 3.4-ounce rule applies to flights departing from the United States, regardless of your destination. If you are flying from another country, that country's airport may have different rules — some are stricter, some are more lenient. Check with your departure airport before you pack.
If you are connecting through a U.S. airport on an international flight, the 3.4-ounce rule applies to your carry-on for the entire journey. If you buy liquids at a duty-free shop after passing through U.S. security, you can bring them on the plane, but only if you are not connecting through another U.S. airport. On a connection, you would need to pack them in checked baggage.
When traveling internationally, it is safest to pack all liquids in checked baggage and buy what you need at your destination. This avoids confusion about different countries' rules and the risk of losing items at a connection.
Travel-size containers and buying liquids at your destination
Travel-size bottles of shampoo, lotion, and other toiletries are sold at drugstores, supermarkets, and travel retailers. These are usually 1 to 3 ounces and fit easily in your liquids bag. Many hotels and airlines also provide small bottles of shampoo and lotion, so you may not need to pack your own at all.
If you are flying with only a carry-on, buying liquids after you pass through security is often easier than packing them. Most airports have shops selling sunscreen, lotion, deodorant, and other basics. Prices are higher than at home, but you avoid the hassle of measuring and packing.
For longer trips, consider shipping a box of toiletries to your hotel ahead of time, or buying them when you arrive. This eliminates the need to pack liquids entirely and gives you more room in your bag for other items.
Frequently Asked Questions
Can I bring a full water bottle through security?
No. You cannot bring any liquid-filled container through TSA security, including water bottles. You can bring an empty water bottle and fill it at a water fountain or refill station after you pass through security. Many airports have these stations near gates.
Do I need to remove my liquids bag if I have TSA PreCheck?
No. TSA PreCheck members can leave liquids in their carry-on bag and do not need to remove shoes, belts, or light jackets. However, the 3.4-ounce rule still applies — containers larger than 3.4 ounces will still be confiscated.
What if my deodorant or toothpaste is solid but comes in a tube?
If it is solid enough that it does not flow or spread, it may be allowed in carry-on baggage without the 3.4-ounce limit. However, TSA officers have discretion to classify borderline items. To be safe, pack gel or liquid deodorant and toothpaste in your liquids bag, or pack solid stick deodorant and solid toothpaste tablets.
Can I bring more than one quart-sized bag of liquids?
No. You are limited to one quart-sized bag per person. If you have more liquids than fit in one bag, you must pack the excess in checked baggage or leave it behind.
Are there any liquids that are completely prohibited?
Yes. Flammable liquids like lighter fluid, paint thinner, and certain cleaning products are prohibited in both carry-on and checked baggage. Aerosols with flammable propellants are also restricted. Check the TSA website or call your airline if you are unsure about a specific item.