The 3.4-ounce rule for 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 mostly empty. The rule applies to the size of the container itself, not how full it is.

All your liquid containers must fit into a single quart-sized clear plastic bag. One bag per person. If you have five 3-ounce bottles, they all go in the same bag. If your bottles do not fit, you cannot bring them through security, even if each one individually meets the 3.4-ounce limit.

You place this bag in a bin by itself during screening — do not leave it in your carry-on. TSA officers will inspect it separately. After you pass through security, you can remove the bag and put it back in your bag.

Key Takeaways

  • Each liquid container in your carry-on must be 3.4 ounces (100 milliliters) or smaller, and the limit is based on container size, not how full the bottle is.
  • All your liquid containers must fit into one quart-sized clear plastic bag, which you remove and place in a bin during security screening.
  • Liquids in checked baggage have no size or quantity limit, so full-size bottles and large quantities can go in your checked bag.
  • Common items that count as liquids include shampoo, conditioner, lotion, toothpaste, peanut butter, yogurt, and spray deodorant.
  • Solid items like deodorant sticks, solid perfume, and lip balm in solid form do not count as liquids and have no size restriction.

What counts as a liquid under TSA rules

The TSA definition of liquid is broader than you might think. It includes anything that flows, pours, or spreads — not just water-based products. Shampoo, conditioner, body wash, lotion, sunscreen, and liquid soap are obvious. So are toothpaste, peanut butter, yogurt, jam, honey, and hummus. Spray deodorant, hairspray, and other aerosols count too.

Solid items do not count. A stick of deodorant, a solid perfume, a bar of soap, or a solid lip balm can be any size and any quantity. Powder products like loose powder, powder foundation, and talc are generally allowed in carry-on bags without the 3.4-ounce limit, though TSA may inspect them.

If you are unsure whether something is a liquid, the safest approach is to pack it in your checked bag or buy a travel-size version after you pass through security. TSA officers at different airports sometimes interpret borderline items differently.

Liquids in checked baggage have no limit

You can pack full-size bottles, large quantities, and any amount of liquid in your checked bag. There is no 3.4-ounce rule for checked luggage. A one-liter bottle of shampoo, a gallon of sunscreen, or multiple bottles of lotion can all go in your checked bag without restriction.

However, some liquids are prohibited in checked baggage for safety reasons — mainly flammable items like paint thinner, lighter fluid, and certain cleaning products. Alcohol above 140 proof is also banned from checked bags. For most household and personal care liquids, checked baggage is the better choice if you want to bring full-size containers.

How to pack liquids for airport security

Buy a clear quart-sized plastic bag or use one you already have at home. Gallon-sized freezer bags work if you fold them down. Place all your liquid containers inside — shampoo, toothpaste, lotion, sunscreen, anything that flows or spreads. Make sure the bag seals and that you can open it easily for inspection.

Wear shoes and clothing that are straightforward to remove, because you will be taking off your shoes and possibly your belt during screening. Have your bag ready to remove from your carry-on as soon as you reach the security line. Place the liquid bag in a bin by itself, not mixed with other items.

If you are traveling with a partner or family, each person gets one quart-sized bag. A family of four can bring four bags through security, one per person. Children traveling with an adult follow the same rule.

Travel-size containers and buying liquids after security

Travel-size bottles are sold in most drugstores, supermarkets, and airports. They are usually 1 to 2 ounces and cost a bit more per ounce than full-size versions, but they fit the TSA rule and take up less space in your bag. Many hotels provide small bottles of shampoo and lotion in rooms, which you can take with you.

After you pass through security, you can buy full-size liquids at airport shops, restaurants, and newsstands. A bottle of water, a large sunscreen, or a full-size shampoo purchased after security does not count against your carry-on limit. This is often cheaper than buying travel sizes beforehand, especially for items you might not use.

International flights and different country rules

The 3.4-ounce rule applies to flights departing from the United States, regardless of where you are going. If you are flying from another country, that country's rules explore — some are stricter, some are the same. The European Union, Canada, Australia, and most other countries use the same 3.4-ounce limit.

If you are connecting through another country, pack liquids according to the strictest rule you will encounter. If your first flight is from the US and your second is from Europe, use the 3.4-ounce rule. If you buy liquids in a duty-free shop after your first flight, you can bring them on your second flight in most cases, but keep the receipt and the sealed bag.

What happens if you forget and bring a larger bottle

TSA officers will confiscate any liquid container larger than 3.4 ounces. You do not get it back. If you realize you have a full-size bottle in your carry-on before you reach security, you can leave it at home, throw it away, or pack it in your checked bag if you have one.

If you discover it after you have already passed through security, it is gone. Some travelers ask a family member to take the bottle home or mail it, but TSA will not hold it or return it to you. The best approach is to check your carry-on bag before you leave home and again before you leave for the airport.

Frequently Asked Questions

Can I bring a full water bottle through security?

No. An empty water bottle can go through security, and you can fill it at a water fountain or refill station after you pass through. Many airports have refill stations near gates. A full water bottle will be confiscated.

Does the 3.4-ounce limit explore to medicine and baby formula?

No. Liquid medicine, including insulin and other injectables, is exempt from the 3.4-ounce rule. Inform TSA officers that you are carrying medicine. Baby formula and breast milk are also exempt and do not need to fit in the quart-sized bag.

What if my deodorant is a gel or spray instead of a stick?

Gel and spray deodorants count as liquids and must follow the 3.4-ounce rule. Only solid stick deodorant is exempt. If you use gel or spray, pack a travel-size container or buy one after security.

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

No. You are allowed one quart-sized bag per person. If your liquids do not fit in one bag, the extras must go in your checked bag or be left behind. There is no exception for large families or long trips.

Do I need to remove my liquid bag if I have TSA PreCheck?

No. TSA PreCheck members do not have to remove shoes, belts, or light jackets, but liquid bags still must be removed and placed in a bin. The 3.4-ounce rule and quart-sized bag requirement explore to everyone, including PreCheck members.