The 3.4-ounce rule for liquids and gels

TSA allows you to bring a single container of liquid or gel that is 3.4 ounces (100 milliliters) or smaller through security. This is the maximum size for any one item. The rule applies to anything that flows, spreads, or is thicker than a solid — toothpaste, shampoo, conditioner, lotion, sunscreen, peanut butter, yogurt, and jam all count as liquids or gels under TSA rules.

You can bring multiple containers as long as each one is 3.4 ounces or less. All of them must fit inside a single quart-sized clear plastic bag. If even one container is larger than 3.4 ounces, TSA will not allow it through security, even if the total volume of all your containers combined is under the limit.

The 3.4-ounce limit applies to carry-on bags only. If you pack liquids and gels in your checked luggage, there is no ounce limit — you can bring full-sized bottles. However, some items like flammable liquids are restricted in checked bags for safety reasons.

Key Takeaways

  • Each liquid or gel container in your carry-on must be 3.4 ounces (100 milliliters) or smaller.
  • All containers must fit together in one quart-sized clear plastic bag at security.
  • If a single container exceeds 3.4 ounces, TSA will remove it even if your total volume is under the limit.
  • Liquids and gels in checked luggage have no ounce restriction, though some items like lighter fluid are banned from checked bags entirely.
  • Common items that count as liquids include toothpaste, deodorant, shampoo, lotion, peanut butter, and yogurt.

What counts as a liquid or gel under TSA rules

TSA defines liquids and gels broadly. The category includes obvious items like water, juice, and shampoo, but also things that may not feel liquid to you. Peanut butter, hummus, yogurt, and pudding are all treated as liquids. Deodorant, sunscreen, and lip balm count as gels. Even solid items that melt or become spreadable at body temperature — like chocolate or coconut oil — fall under the liquid rule.

Powders are treated differently. Powders like talc, baby powder, protein powder, and flour have no ounce limit in carry-on bags, though TSA may open and test them at security. If you have more than 12 ounces of powder in your carry-on, TSA may require additional screening.

Medications in liquid or gel form are allowed in carry-on bags in quantities larger than 3.4 ounces, but you must declare them to TSA officers at security. Bring the medication in its original labeled container and tell the officer it is a medication before you go through the scanner.

How to pack your liquids bag for security

Use a clear quart-sized plastic bag — the kind that measures roughly 7 inches by 8 inches. Place all your liquid and gel containers inside it so TSA officers can see them without opening the bag. Each container must be 3.4 ounces or smaller. Seal the bag completely before you reach the security checkpoint.

Place your liquids bag on top of your other carry-on items when you put your bag on the conveyor belt. You will remove it and place it in a bin by itself during screening. Do not mix it with electronics, shoes, or other items — TSA needs a clear view of the contents.

If you forget to pack your liquids bag separately, TSA will ask you to step aside while they inspect your carry-on more thoroughly. This slows down your screening, so packing correctly the first time saves time at the checkpoint.

What happens if a container is slightly over 3.4 ounces

TSA will not allow it through security. The rule is firm: 3.4 ounces or smaller. A container that is 3.5 ounces will be confiscated, even if the difference is tiny. TSA officers do not have discretion to allow oversized containers.

If you are unsure whether a container meets the size limit, check the label. The ounce measurement is usually printed on the bottom or back. If the label says 3.4 oz or 100 mL or less, you are within the limit. If it says 3.5 oz, 4 oz, or any amount larger, TSA will remove it.

You can purchase travel-sized versions of most products — shampoo, conditioner, lotion, and toothpaste all come in 3.4-ounce bottles designed for air travel. These are widely available at drugstores and online, and they cost more per ounce than full-sized bottles but are worth the convenience if you travel often.

Liquids in checked luggage have no ounce limit

You can pack full-sized bottles of shampoo, lotion, perfume, and other liquids in your checked bag without any ounce restriction. There is no limit on how many bottles you can bring or how large they can be, as long as they fit in your suitcase.

However, some liquids are banned from checked luggage for safety reasons. Flammable items like lighter fluid, paint thinner, and some types of nail polish remover cannot go in checked bags. Alcohol above 140 proof is also restricted. Check TSA's website or call your airline before packing if you are unsure whether a specific liquid is allowed in checked luggage.

If you are checking a bag, consider packing all your liquids there instead of carrying them on. This eliminates the need to measure containers and fit them into a quart-sized bag, and you can bring full-sized products that last longer.

International flights and different country rules

The 3.4-ounce rule applies to flights departing from the United States. If you are flying internationally, the same rule applies to your carry-on bag when you leave the U.S. However, some countries have different rules for flights departing from their airports.

If you are connecting through another country, you may need to follow that country's liquid rules for the next leg of your journey. For example, some European airports have the same 3.4-ounce limit, while others may differ. Check the rules for each airport you will pass through before you pack.

If you purchase liquids in a duty-free shop after passing through security at a U.S. airport, you can bring them on your flight. However, if you are connecting to another flight, you may need to pack them in checked luggage for the second flight, depending on that airport's rules.

Frequently Asked Questions

Can I bring a full water bottle through TSA security?

No. You cannot bring any liquid through security, including water. You can bring an empty water bottle and fill it at a water fountain or refill station after you pass through security. Many airports have water refill stations near gates.

Does sunscreen count toward the 3.4-ounce limit?

Yes. Sunscreen is classified as a gel and must be 3.4 ounces or smaller in your carry-on bag. Travel-sized sunscreen bottles are widely available and fit the TSA limit.

What if I have prescription liquid medication?

Prescription medications in liquid form are allowed in quantities larger than 3.4 ounces in your carry-on bag. Bring the medication in its original labeled container and declare it to TSA at security before screening. You do not need to place it in your liquids bag.

Can I bring a 3.4-ounce container of peanut butter?

Yes, as long as it is exactly 3.4 ounces or smaller. Peanut butter is treated as a liquid or gel under TSA rules. Check the label to confirm the size before packing.

What if my deodorant is labeled in milliliters instead of ounces?

Convert milliliters to ounces: 100 milliliters equals 3.4 ounces. If your container says 100 mL or less, it meets the TSA limit. If it says more than 100 mL, it does not.