Liquids, gels, and aerosols: the 3.4-ounce rule

You can bring a container of liquid, gel, or aerosol through a TSA checkpoint only if it holds 3.4 ounces (100 millilitres) or less. This limit applies to each individual container, not to the total amount you carry. A bottle of shampoo that is 3.4 ounces is allowed; one that is 3.5 ounces is not.

All containers that hold 3.4 ounces or less must fit inside a single clear plastic bag, roughly the size of a quart. You place this bag in a bin at the checkpoint, and TSA officers screen it separately from your carry-on luggage. You can pack larger containers of the same items in your checked baggage without restriction.

This rule covers anything that flows, spreads, or sprays: shampoo, conditioner, lotion, toothpaste, sunscreen, deodorant, perfume, cologne, liquid makeup, peanut butter, yogurt, honey, and jam. Solid items like bar soap, solid deodorant, and lipstick do not count toward the limit.

Key Takeaways

  • Each liquid, gel, or aerosol container in your carry-on must be 3.4 ounces (100 millilitres) or smaller.
  • All containers fitting the size limit go into one clear quart-sized plastic bag, which you remove at the checkpoint.
  • Checked baggage has no ounce limit for liquids, gels, or aerosols, though some items remain prohibited entirely.
  • Solid items like bar soap, solid deodorant, and toothpaste tablets do not count toward the 3.4-ounce limit.
  • TSA officers may confiscate containers that exceed 3.4 ounces, even if they are partially full.

What counts as a liquid, gel, or aerosol

TSA defines liquids broadly. The category includes obvious liquids like water, juice, and soup, but also creams, pastes, gels, and anything that can be poured or spread. Peanut butter, hummus, and other thick spreads count. Aerosol cans — deodorant, hairspray, shaving cream — count even though they are not technically liquid.

The rule also covers items that are solid at room temperature but become liquid when heated or when you explore pressure. Lipstick, for example, is a solid stick, but TSA treats it as a gel and allows it in carry-on without the bag restriction. Solid deodorant sticks are allowed without the bag. Toothpaste is a paste and must go in the quart bag.

If you are unsure whether an item counts, the safest approach is to pack it in checked baggage or buy it after you pass the checkpoint. TSA officers have final say at the checkpoint, and they may confiscate an item even if you believe it is solid.

Measuring and packing your liquids bag

The container size is what matters, not how much liquid is actually inside. A 3.4-ounce bottle that is half-full still counts as a 3.4-ounce container and is allowed. A 4-ounce bottle that is one-quarter full is not allowed, because the container itself exceeds 3.4 ounces.

You can buy a quart-sized clear plastic bag at most drugstores and supermarkets, or TSA provides them free at some checkpoints. The bag must be clear so officers can see inside without opening it. Pack containers tightly so the bag closes easily. Containers should not leak, but placing them in the bag gives you a safety margin if one does.

Remove the bag from your carry-on before you reach the checkpoint scanner. Place it in a bin by itself. After screening, you can return it to your carry-on or keep it separate — TSA does not care once it has been screened.

Items prohibited entirely in carry-on and checked baggage

Some items cannot travel in either carry-on or checked baggage, regardless of ounces. These include flammable liquids like lighter fluid and paint thinner, certain pesticides, and some types of batteries. Firearms, explosives, and realistic replicas of weapons are prohibited in both.

Other items are allowed in checked baggage but not in carry-on. These include certain tools, sporting equipment with sharp edges, and some types of lighters. Checked baggage rules are more lenient because the bag is not in the passenger cabin during flight.

Before packing anything you are uncertain about, check the TSA website's "What Can I Bring?" tool or contact TSA directly. Rules can vary slightly by airport, and some items require special handling or declaration.

Solid and powder exceptions

Solid items do not fall under the 3.4-ounce limit for carry-on. You can bring a full-sized bar of soap, a solid deodorant stick, or a toothpaste tablet without packing them in the quart bag. Solid cosmetics like eyeshadow palettes and powder blush are allowed in any quantity.

Powders are treated differently depending on quantity. Powders in containers larger than 12 ounces may require additional screening or may be prohibited in carry-on. Powders in smaller containers — like loose powder makeup or protein powder under 12 ounces — are generally allowed but may be opened and tested at the checkpoint.

If you are traveling with powder, pack it where you can easily access it for inspection. TSA may swab it or run it through a machine to test for explosives or other prohibited substances.

What happens if you exceed the limit

If a container exceeds 3.4 ounces and is not in the quart bag, TSA will confiscate it at the checkpoint. You do not get it back. If you discover the problem before you reach the checkpoint, you can ask a TSA officer where the nearest trash bin is, or you can check the item in your luggage if you have time to do so.

TSA does not charge a fee for confiscation, but you lose the item and the money you spent on it. If you are traveling with expensive skincare or medications, double-check container sizes before you pack.

If you are unsure whether an item will be allowed, arrive early and ask a TSA officer before you go through the scanner. They can tell you whether the item is prohibited or whether it needs to go in the quart bag.

Medications and medical liquids

Liquid medications and medical liquids like saline solution are allowed in carry-on in quantities larger than 3.4 ounces, but you must declare them to TSA. Remove them from your quart bag and place them in a separate bin. Tell the officer that you are traveling with medication.

You do not need a prescription or doctor's note, but having one makes the process faster. Insulin, for example, is allowed in any quantity if you declare it. Breast milk and formula are also exempt from the 3.4-ounce limit if you are traveling with an infant.

Pack medications in their original labeled containers when possible. If a medication is in a generic or travel-sized container, a prescription label or doctor's note helps explain what it is.

Frequently Asked Questions

Can I bring a full-sized bottle of shampoo in my carry-on?

No, unless the bottle is 3.4 ounces or smaller. Full-sized bottles are typically 8 to 16 ounces. Pack a travel-sized bottle in your carry-on quart bag, or pack the full-sized bottle in checked baggage with no limit.

Do I need to buy a quart-sized bag, or can I use any clear plastic bag?

The bag must be roughly quart-sized (about 7 inches by 8 inches). A sandwich bag is too small. A gallon bag is too large. TSA provides free bags at some checkpoints, but it is safer to bring your own to avoid delays.

What if my toothpaste tube says 4 ounces but is mostly empty?

TSA measures by container size, not by how much product is inside. A 4-ounce tube is not allowed in carry-on, even if it is nearly empty. Either pack it in checked baggage or buy a travel-sized tube that is 3.4 ounces or smaller.

Are solid deodorant and liquid deodorant treated differently?

Yes. Solid deodorant sticks are not subject to the 3.4-ounce limit and do not need to go in the quart bag. Liquid or gel deodorant must be 3.4 ounces or smaller and must go in the bag.

Can I bring honey or peanut butter through the checkpoint?

Yes, if the container is 3.4 ounces or smaller and goes in your quart bag. Larger containers must be packed in checked baggage. Both are treated as gels under TSA rules.