The 3.4-ounce rule for liquids in carry-on bags

The TSA (Transportation Security Administration) limits liquids, gels, and aerosols in carry-on luggage to 3.4 ounces (100 millilitres) per container. All containers must fit inside a single quart-sized clear plastic bag. You can bring multiple containers as long as each one is 3.4 ounces or smaller and they all fit in that one bag.

This rule applies to flights departing from U.S. airports. If you are flying internationally or connecting through another country, check that country's rules — some are stricter. The limit exists because the TSA classifies certain liquids as potential security risks when carried in large quantities in the cabin of an aircraft.

The 3.4-ounce limit is per container, not per item type. You can bring a 3.4-ounce bottle of shampoo and a 3.4-ounce bottle of conditioner, for example, as long as both fit in your quart bag.

Key Takeaways

  • Each liquid container in your carry-on must be 3.4 ounces (100 millilitres) or smaller, and all containers together must fit in one quart-sized clear plastic bag.
  • Liquids include shampoo, conditioner, lotion, toothpaste, peanut butter, yogurt, honey, and any product that flows or spreads — not just water-based items.
  • You can pack full-sized bottles of liquids in checked baggage with no size limit, so consider moving items there if you have room.
  • The TSA provides free quart-sized bags at security checkpoints, but bringing your own saves time in the line.
  • International flights and connections may have different rules, so check your airline and destination country before packing.

What counts as a liquid under TSA rules

The TSA defines liquids broadly. Beyond water, juice, and soda, the category includes shampoo, conditioner, body wash, lotion, sunscreen, toothpaste, deodorant (if it is a gel or cream), mascara, foundation, lip gloss, peanut butter, yogurt, honey, jam, and anything else that flows, spreads, or sprays. Solid deodorant is allowed in carry-on bags without restriction.

Medications in liquid or gel form count toward the limit, but you can bring them in quantities larger than 3.4 ounces if you declare them to the TSA officer at security. Pack them separately from your quart bag and tell the officer before screening begins.

Frozen items are treated as liquids if they are still partially frozen when you reach the security checkpoint. A completely solid frozen item (like a frozen water bottle) is allowed, but ice packs and partially thawed items will be confiscated.

How to pack your liquids bag correctly

Use a clear quart-sized plastic bag — the TSA provides them free at security, but you can bring your own to move faster through the line. Place all containers 3.4 ounces or smaller inside the bag and seal it. The bag itself must fit easily in a security bin.

Arrange containers so the TSA officer can see them without removing them from the bag. Tightly seal all containers before packing to prevent leaks. If a container leaks and damages other items in your carry-on, the TSA is not responsible.

Remove your liquids bag from your carry-on before you reach the security checkpoint and place it in a bin on the conveyor belt. This speeds up screening. After you pass through security, you can return the bag to your carry-on.

Packing liquids in checked baggage instead

Checked baggage has no size limit for liquids, gels, or aerosols. If you have full-sized bottles of shampoo, lotion, or other liquids, pack them in your checked bag instead of your carry-on. This avoids the 3.4-ounce restriction entirely.

Seal containers tightly to prevent leaks during handling. Place them in a separate plastic bag inside your checked luggage in case of spillage. Some airlines limit the total quantity of hazardous materials (like aerosol sprays or flammable items) even in checked bags, so check your airline's baggage policy before packing.

Rules for different types of flights

Domestic flights within the United States follow the TSA's 3.4-ounce rule. International flights departing from U.S. airports also follow this rule, but the destination country may have stricter limits on what you can bring into that country after landing.

If you are connecting through another country, that country's rules explore to your carry-on during the connection. For example, if you fly from New York to London and then to Paris, you must follow both U.K. and French liquid rules. Many European airports use the same 100-millilitre (3.4-ounce) limit, but some countries are more restrictive.

Check your airline's website and your destination country's customs rules before packing. Rules change, and some countries have temporary restrictions that are not widely publicized.

What happens if you forget about the liquid limit

If you arrive at security with liquids that exceed the 3.4-ounce limit or that do not fit in a quart bag, the TSA officer will ask you to throw them away, leave them at security, or check your carry-on bag instead. You cannot bring oversized liquid containers through the checkpoint.

Some airports have mail services or package shipping options near security if you want to mail items to yourself rather than discard them. This is slower and more expensive than packing correctly the first time, but it is an option if you have expensive products.

Arriving at the airport early gives you time to handle this situation without missing your flight. If you are unsure whether an item is allowed, ask the TSA officer before placing it on the conveyor belt.

Frequently Asked Questions

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

No. Full-sized bottles are almost always larger than 3.4 ounces. You can bring travel-sized bottles (3.4 ounces or smaller) in your carry-on, or pack full-sized bottles in your checked bag instead. Many hotels provide shampoo, so you may not need to pack it at all.

Do I need to buy a quart-sized bag, or can I use a sandwich bag?

A standard sandwich bag is too small. The TSA requires a quart-sized bag, which is roughly 7 by 8 inches. The TSA provides them free at security checkpoints, or you can buy them at drugstores and supermarkets before you travel.

Are solid deodorants allowed in carry-on luggage?

Yes. Solid stick deodorant is not classified as a liquid and has no size limit in carry-on bags. Gel, cream, or spray deodorants count as liquids and must follow the 3.4-ounce rule.

What if my medication is a liquid and I need more than 3.4 ounces?

Pack it separately from your quart bag and declare it to the TSA officer at security before screening begins. Medications in liquid or gel form are allowed in quantities larger than 3.4 ounces if you inform the officer. Bring a prescription label or doctor's note if possible.

Can I bring a water bottle through security?

No, not if it contains liquid. Empty water bottles are allowed, and you can fill them at water fountains or refill stations after you pass through security. Many airports have bottle-filling stations near gates.