The 3.4-ounce limit per container, 1 quart bag total

The TSA allows you to bring liquids, gels, and aerosols through security in containers of 3.4 ounces (100 millilitres) or smaller. All containers must fit inside a single clear plastic bag that holds about 1 quart total. You get one bag per person, and it goes in a bin during screening.

This rule applies to carry-on bags only. Checked luggage has no liquid restrictions, so you can pack full-size bottles there if you want. The 3.4-ounce rule exists because the TSA treats liquids as a potential security risk at the checkpoint, even though checked bags go through different screening.

The measurement is by volume, not weight. A 3.4-ounce container of honey and a 3.4-ounce container of water take up the same space in your quart bag, even though honey weighs more. If a container says 3.4 fl oz or 100 ml, it passes. If it says 3.5 fl oz or 101 ml, it does not.

Key Takeaways

  • Each liquid container in your carry-on must be 3.4 ounces (100 ml) or smaller by volume.
  • All containers together must fit inside one clear quart-sized plastic bag.
  • You can bring as many 3.4-ounce containers as fit in the bag—there is no limit on the number of bottles, only the size of each one.
  • Checked baggage has no liquid restrictions, so full-size bottles go in your suitcase, not your carry-on.
  • Solid products like deodorant sticks, lip balm, and peanut butter are not liquids and do not need to go in the bag.

What counts as a liquid under this rule

The TSA defines liquids broadly: water, juice, yogurt, peanut butter, honey, jam, salsa, and soup all count. So do gels like toothpaste, shampoo, and hair gel. Aerosols like deodorant spray, sunscreen spray, and hairspray count too. Creams, lotions, and oils count. If it pours, spreads, or sprays, assume it is a liquid.

Solid or semi-solid products are not liquids. A stick of deodorant, a bar of soap, a tube of lipstick, a solid perfume, or a stick of lip balm can go anywhere in your carry-on. Peanut butter in a jar is a liquid; a peanut butter sandwich is not. Toothpaste is a gel; a toothpick is not.

Frozen items are treated as solids if they are completely frozen when you reach the checkpoint. Ice is allowed. A frozen gel pack is allowed. But anything that is melting or slushy gets treated as a liquid, so pack frozen items in the middle of your bag with insulation around them if you want them to stay solid through security.

How to pack your quart bag correctly

The TSA provides free quart-sized clear plastic bags at airport security, or you can bring your own. Any clear plastic bag about the size of a gallon-sized freezer bag works—it does not have to be a special TSA bag. The point is that screeners need to see inside without opening it.

Put all your liquid containers in the bag and seal it. At the checkpoint, remove the bag from your carry-on and place it in a bin by itself. You do not need to remove individual bottles unless a screener asks. The bag goes through the X-ray machine, and you pick it up on the other side.

Pack your bag so that nothing leaks on your other belongings. If a container opens during the flight or in your bag, you want the damage contained. Wrap bottles in plastic wrap or put them in smaller bags inside the quart bag if you are worried about spills.

Exceptions and items that bypass the liquid rule

Medications in liquid form are exempt from the 3.4-ounce limit. You can bring a full bottle of liquid medicine, cough syrup, or insulin without restriction. Tell the screener that you have medication before you reach the checkpoint. You do not have to put it in the quart bag, though you can if you want.

Baby formula, breast milk, and baby food are also exempt. You can bring as much as you need for your flight. Again, tell the screener before screening begins. These items do not go in the quart bag.

Duty-free liquids purchased after you pass through security at your departure airport can travel in your carry-on to your destination, even if they exceed 3.4 ounces. The store gives you a special sealed bag. Keep that bag sealed and unopened until you reach your final destination. If you open it before landing, the contents become subject to the 3.4-ounce rule at your next connection.

What happens if you bring too much liquid

If a screener finds a container larger than 3.4 ounces or a quart bag that does not fit the limit, they will ask you to throw it away, check it, or leave it behind. You cannot bring it through security. There is no fine or penalty—the item is straightforward not allowed in the carry-on.

If you have a container that is close to the limit but you are not sure, ask the screener. They have the final say. It is better to ask than to have the item confiscated at the checkpoint.

Packing liquids in checked baggage instead

Checked bags have no liquid restrictions. You can pack full-size bottles of shampoo, sunscreen, cologne, or any other liquid. The bag goes in the cargo hold, which is pressurized and temperature-controlled like the cabin, so your bottles will not explode.

Wrap bottles in plastic bags or wrap them in clothing to prevent leaks. If a bottle breaks in your checked bag, the damage is contained and does not affect other passengers. Many travelers pack all their liquids in checked luggage to avoid the quart-bag hassle entirely.

If you are flying with only a carry-on and no checked bag, you are limited to the 3.4-ounce rule. Some travelers buy travel-size bottles before the trip, or they buy full-size bottles after they land.

International flights and connecting flights

The 3.4-ounce rule applies to all flights departing from a U.S. airport, whether domestic or international. If you are connecting through a U.S. airport, you will go through security again at the connection, and the rule applies again.

If you buy liquids at a duty-free shop after passing through U.S. security, keep them sealed in the special bag the store provides. When you reach your connecting airport, that sealed bag can go in your carry-on. Once you open it or reach your final destination, the contents are no longer protected.

If you are flying from a non-U.S. airport, that country's rules explore. Many countries follow the same 3.4-ounce limit, but some do not. Check the security rules for your departure airport before you pack.

Frequently Asked Questions

Can I bring a full water bottle through security?

No. An empty water bottle is fine, but a full one exceeds the 3.4-ounce limit. Fill it after you pass through security at a water fountain or bottle-filling station. Most U.S. airports have them near the gates.

Does the 3.4-ounce limit include the weight of the container itself?

No. The 3.4 ounces refers to the volume of liquid inside, not the total weight of the bottle plus liquid. A 3.4-ounce container of honey (which is heavier than water) is still allowed because the volume is 3.4 ounces.

What if my deodorant says 3.8 ounces—can I bring it?

Only if it is a solid stick. Solid deodorant is not a liquid and does not count toward the limit. If it is a spray or gel, it exceeds the 3.4-ounce limit and cannot go in your carry-on. Check it or buy a travel size.

Can I bring multiple quart bags if I have a lot of liquids?

No. The rule is one quart bag per person. If your liquids do not fit in one bag, you must check the extras or leave them behind. You cannot bring two bags through security.

Do I need to remove my quart bag from my carry-on at every checkpoint?

Yes. At U.S. airport security, you must remove the quart bag and place it in a bin. Some international airports have different rules, so follow the signs and instructions at your departure airport.