The 3-1-1 Rule: What TSA Allows in Carry-On Bags
You can bring liquids, gels, and aerosols through TSA security in carry-on bags only if they follow the 3-1-1 rule: each container holds 3.4 ounces (100 milliliters) or less, all containers fit inside one clear quart-sized plastic bag, and you have one bag per person. Anything larger than 3.4 ounces must go in checked baggage instead.
The 3-1-1 rule applies to anything that flows, spreads, or sprays—not just water. Toothpaste, shampoo, conditioner, lotion, sunscreen, deodorant, peanut butter, yogurt, honey, and jam all count as liquids under TSA rules. Solid foods like granola bars, cheese, and apples do not.
You remove your quart-sized bag from your carry-on at the security checkpoint and place it in the bin with your shoes and electronics. After you pass through security, you can put it back in your bag. If you forget to remove it, TSA will find it during screening and confiscate the entire bag—not just the oversized bottles.
Key Takeaways
- Each liquid container in your carry-on must be 3.4 ounces (100 milliliters) or smaller, and all containers must fit in one clear quart-sized bag.
- Liquids larger than 3.4 ounces can travel in checked baggage with no size limit, so pack full-sized bottles below the plane instead of in your carry-on.
- You must remove your quart-sized liquid bag at the security checkpoint and place it in a bin, just like shoes and laptops.
- Common items that count as liquids include toothpaste, shampoo, lotion, sunscreen, peanut butter, yogurt, and any gel or aerosol spray.
What Counts as a Liquid Under TSA Rules
TSA defines liquids broadly to include anything that is not a solid at room temperature. This covers obvious liquids like water, juice, and coffee, but also gels, creams, pastes, and aerosols. If you are unsure whether something counts, the safest approach is to pack it in your quart-sized bag or put it in checked baggage.
Common items that must follow the 3-1-1 rule include shampoo, conditioner, body wash, lotion, moisturizer, sunscreen, deodorant (spray or gel), toothpaste, mouthwash, hair gel, mascara, liquid eyeliner, foundation, concealer, and any cream or ointment. Food items like peanut butter, jam, honey, yogurt, pudding, and sour cream also count as liquids.
Solid foods do not count. You can pack a full-sized jar of peanut butter in your carry-on if you want, but a tube of toothpaste the same size cannot go through security. Medications in liquid or gel form follow the same 3.4-ounce rule, though you can bring more if you declare them and show a prescription or label with your name.
Packing Liquids in Checked Baggage
Checked baggage has no size limit for liquids. You can pack full-sized bottles of shampoo, sunscreen, lotion, and other toiletries in your checked bag without restriction. This is the easiest option if you need more than 3.4 ounces of something and do not want to buy travel-sized bottles at your destination.
Pack liquids in the center of your checked bag, surrounded by clothes or towels, to reduce the risk of leaks damaging other items. If a bottle does leak, the damage stays contained to your bag instead of spreading to other passengers' luggage on the conveyor belt. Some travelers wrap bottles in plastic bags or place them in a separate toiletry case for extra protection.
Checked baggage does have restrictions on certain hazardous liquids—flammable items like lighter fluid, paint thinner, and some cleaning products are not allowed in checked bags either. Alcohol over 140 proof is also prohibited. For most everyday toiletries and food items, checked baggage is unrestricted.
How to Pack Your Quart-Sized Bag Correctly
Buy a clear quart-sized plastic bag (one-liter freezer bags work) or use the complimentary bags TSA sometimes provides at security. Place all your liquid containers inside—they do not have to be perfectly arranged, but they must all fit and the bag must close. If a container does not fit, it is too large or you have too many items.
Arrange containers so TSA officers can see everything inside without opening the bag. Place heavier items on the bottom so lighter ones do not get crushed. If you are traveling with multiple people, each person gets one quart-sized bag, so a family of four can bring four bags total.
At the checkpoint, remove your bag before you reach the security officer and place it in a bin by itself or with your shoes and electronics. Do not wait for the officer to ask—having it ready speeds up the line. After screening, you can put the bag back in your carry-on.
Exceptions and Special Cases
Medications in liquid or gel form are exempt from the 3.4-ounce limit if you declare them. Place them in a separate bag (not your quart-sized toiletries bag) and tell the officer you are carrying medication. You will need to show the prescription label or a doctor's note with your name on it. Insulin and other essential medications are always allowed.
Breast milk and formula are also exempt from the 3-1-1 rule. You can bring more than 3.4 ounces in your carry-on if you declare it. Frozen breast milk or formula is allowed if it is completely frozen solid at the checkpoint, but partially frozen or thawed milk must follow the 3-1-1 rule.
Duty-free alcohol purchased after security is an exception to the carry-on liquid rule. You can bring a sealed duty-free bag through security and onto the plane, even though the bottle is larger than 3.4 ounces. The bag must remain sealed and unopened during the flight. Once you land, you can open it.
What Happens If You Forget Your Liquids Bag
If you reach the security checkpoint without removing your quart-sized bag from your carry-on, TSA will discover it during screening. The officer will ask you to remove it, and if the bag or any individual container violates the 3-1-1 rule, the entire bag will be confiscated. You will not get to keep the bag and discard only the oversized items—TSA discards the whole thing.
This is why packing correctly before you arrive at the airport matters. Spend two minutes organizing your liquids into a quart-sized bag at home, and you avoid the frustration of losing items at security. If you realize you forgot after you are already in line, tell an officer when ready—some checkpoints have a courtesy area where you can repack before screening.
If you are unsure whether something is allowed, ask a TSA officer before you go through the scanner. They can tell you whether an item counts as a liquid and whether it needs to go in your quart-sized bag or checked luggage. It is better to ask than to lose the item.
International Flights and Different Rules
The 3-1-1 rule applies to flights departing from U.S. airports, including connecting flights. If you are flying from another country, that country's airport may have different rules. Some international airports allow larger containers or do not require a quart-sized bag. Check the website of your departure airport before you pack.
If you are connecting through a U.S. airport on an international flight, you must follow U.S. rules for the first leg of your journey. If you buy liquids at a duty-free shop in a U.S. airport during a layover, you can bring them on your next flight only if they are in a sealed duty-free bag. Once you open the bag, the contents must follow the 3-1-1 rule for any subsequent flights.
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 the checkpoint. A full water bottle will be confiscated because water is a liquid and exceeds the 3.4-ounce limit.
Do solid deodorant and spray deodorant follow the same rule?
No. Solid stick deodorant is not a liquid and does not count toward the 3-1-1 rule. Spray deodorant and gel deodorant are aerosols or gels and must be 3.4 ounces or smaller in your carry-on. Solid deodorant can be any size in your carry-on.
What if my toothpaste tube says it is 4 ounces but looks small?
The label size is what matters, not how full the tube is. If the tube is labeled 4 ounces, it exceeds the 3.4-ounce limit and must go in checked baggage or be left behind. Buy a travel-sized tube (usually 0.8 to 1.5 ounces) for your carry-on.
Can I bring multiple quart-sized bags if I have a lot of liquids?
No. Each person is allowed one quart-sized bag. If you have more liquids than fit in one bag, the extras must go in checked baggage. Do not try to bring two bags through security—TSA will confiscate the second one.
Are there liquids I cannot bring in checked baggage either?
Yes. Flammable liquids like lighter fluid, paint thinner, and some cleaning products are prohibited in both carry-on and checked baggage. Alcohol over 140 proof is also prohibited. For most toiletries and food items, checked baggage is unrestricted.