The 3.4-ounce limit for liquids in carry-on bags
You can bring a single container of liquid, gel, paste, or aerosol through TSA security in your carry-on bag only if it holds 3.4 ounces (100 milliliters) or less. This is the maximum size for any one item. The rule applies to anything that flows, spreads, or sprays—shampoo, toothpaste, peanut butter, yogurt, sunscreen, cologne, and hundreds of other products all count.
The 3.4-ounce limit is a hard boundary. A container with 3.5 ounces will be confiscated. TSA officers measure by the container's labeled size, not how full it actually is, so an empty 5-ounce bottle counts as a 5-ounce container and cannot pass through.
This rule applies only to carry-on bags. Liquids in checked baggage have no size limit per container, though airlines may have their own restrictions on hazardous materials. If you need more than 3.4 ounces of something in your carry-on, you must pack it in checked luggage instead.
Key Takeaways
- Each liquid container in your carry-on can hold no more than 3.4 ounces; TSA measures the container size, not how full it is.
- The rule covers anything that flows, spreads, or sprays: shampoo, toothpaste, lotion, peanut butter, yogurt, jam, and aerosols all count as liquids.
- You can bring multiple containers as long as each one is 3.4 ounces or smaller and they all fit inside a single quart-sized clear plastic bag.
- Liquids in checked baggage have no per-container size limit, so pack larger bottles there if you need them.
- TSA officers can confiscate any liquid container larger than 3.4 ounces at the security checkpoint; there is no exception for nearly-empty bottles.
The quart-sized bag rule for multiple containers
If you are bringing more than one liquid container, all of them must fit inside a single quart-sized clear plastic bag. A quart bag measures roughly 7 inches by 8 inches. You can bring multiple 3.4-ounce containers—for example, a 3.4-ounce shampoo, a 3.4-ounce conditioner, and a 3.4-ounce lotion—as long as they all fit in one bag and each container is 3.4 ounces or smaller.
You must remove this bag from your carry-on at the security checkpoint and place it in the bin for screening. TSA provides free quart bags at most checkpoints, but you can also bring your own. The bag must be clear so officers can see inside without opening it.
Solid items do not count toward the bag limit. Deodorant stick, lipstick, and a bar of soap can travel with you without taking up space in the quart bag. Only items that are liquid, gel, paste, or aerosol need to go in the bag.
What counts as a liquid under TSA rules
TSA defines liquids broadly. The category includes obvious liquids like water, juice, and shampoo, but also gels (hair gel, aloe vera), pastes (toothpaste, peanut butter), creams (lotion, sunscreen), and aerosols (deodorant spray, hairspray). Peanut butter, yogurt, jam, honey, and hummus all count as pastes and are subject to the 3.4-ounce limit in carry-on bags.
Solid or semi-solid items that do not spread or flow are not liquids. A stick of deodorant, a bar of soap, a lipstick, and a solid perfume are allowed in any quantity. Cheese, chocolate, and other foods that hold their shape are also permitted. The question is whether the item will spread or flow if the container breaks—if yes, it is a liquid.
Some items fall into a gray area. Mascara, for example, is a paste and counts as a liquid. Lip balm in a tube is usually allowed because it is solid enough not to flow. If you are unsure about a specific product, check the TSA website or ask an officer before you reach the front of the security line.
Medications, baby formula, and breast milk exceptions
Medications in liquid or gel form are exempt from the 3.4-ounce limit in carry-on bags. You can bring a full bottle of liquid prescription medication, cough syrup, or insulin without packing it in the quart bag. Inform the TSA officer that you are carrying medication before screening begins.
Baby formula and breast milk are also exempt from the 3.4-ounce rule. You can bring as much as you need for your flight in your carry-on. You do not need to pack them in the quart bag. Again, tell the officer what you are carrying so they can screen it appropriately.
Gel ice packs and frozen items are treated differently depending on their state. A completely frozen gel pack can travel in carry-on luggage. A partially frozen or thawed gel pack is treated as a liquid and must follow the 3.4-ounce rule. Frozen food is allowed if it is completely solid when you reach the checkpoint.
What happens if you try to bring a container that is too large
If a TSA officer finds a liquid container larger than 3.4 ounces in your carry-on bag, they will confiscate it. You do not get it back. There is no option to check it at that point—you are already past the point where you can reroute your bag to checked luggage. The item is discarded.
This is why it is worth checking your carry-on before you arrive at the airport. If you have a full-size bottle of shampoo or a large jar of face cream, move it to your checked bag now rather than discovering it at security and losing it.
TSA does not charge a fee for confiscating items, and officers are not able to make exceptions based on the cost or sentimental value of what you are carrying. The rule is enforced consistently at every checkpoint.
Packing liquids for a checked bag
Liquids in checked baggage do not have to follow the 3.4-ounce rule, but they do need to be packed safely so they do not leak and damage other items or the aircraft. Place each liquid container in a separate plastic bag, or wrap it in plastic wrap or a plastic grocery bag. If a bottle leaks during handling, the plastic will contain the spill.
Some liquids are considered hazardous materials and cannot be packed in checked baggage at all. These include paint, paint thinner, certain cleaning products, and some perfumes with high alcohol content. Your airline's website lists prohibited hazardous materials, or you can call their customer service line to ask about a specific product.
Pack heavier items like full bottles of shampoo and lotion at the bottom of your checked bag, away from fragile items. Pressure changes during flight can cause bottles to leak even if they are sealed, so extra protection is worth the space.
International flights and TSA PreCheck
The 3.4-ounce liquid limit applies to all flights departing from the United States, whether you are flying domestically or internationally. If you are connecting through a U.S. airport on an international journey, the rule applies at every U.S. checkpoint.
TSA PreCheck members still follow the same 3.4-ounce rule for liquids in carry-on bags. PreCheck speeds up screening in other ways—you can keep shoes and light jackets on, leave laptops in bags, and use a dedicated security lane—but the liquid limit does not change. You still need to pack liquids in a quart bag and remove it for screening.
Some international airports have different rules for liquids purchased after you pass security. Liquids bought in a duty-free shop or airport store after you clear security can sometimes be larger than 3.4 ounces, but only if they are in a sealed, tamper-evident bag. Rules vary by country and airport, so check before you buy.
Frequently Asked Questions
Can I bring a full water bottle through security if I fill it after I pass the checkpoint?
Yes. You cannot bring a full water bottle through security, but you can bring an empty bottle and fill it at a water fountain or refill station after you pass the checkpoint. Many airports have free water refill stations near gates. This saves money and lets you stay hydrated on your flight.
Do solid deodorants and antiperspirants count as liquids?
Solid stick deodorant and antiperspirant are not liquids and do not count toward the 3.4-ounce limit. Deodorant spray and aerosol antiperspirant are liquids and must follow the rule. Check the product label to see whether it is a stick, spray, or gel.
What if my toothpaste tube says 4 ounces but it is mostly empty?
TSA measures by the container's labeled size, not how much product is actually inside. A 4-ounce tube will be confiscated even if it is nearly empty. Buy a travel-size tube labeled 3.4 ounces or smaller, or pack your regular tube in checked baggage.
Can I bring multiple quart bags if I have a lot of liquids?
No. You are allowed one quart-sized bag per person. If you have more liquids than fit in one bag, the extras must go in checked luggage. Plan ahead and move larger bottles to your checked bag before you arrive at the airport.
Are there any liquids that are completely banned from both carry-on and checked bags?
Yes. Certain hazardous materials like gasoline, lighter fluid, and some cleaning products cannot travel on passenger aircraft in either carry-on or checked baggage. Your airline's website lists prohibited items, or contact them directly if you are unsure about a specific product.