The TSA 3-1-1 Rule for Liquids and Gels

The single biggest restriction on carry-on packing is the 3-1-1 rule for liquids, gels, and aerosols. You can bring these items, but each container must hold 3.4 ounces (100 milliliters) or less, all containers must fit inside one clear quart-sized plastic bag, and you get only one bag per person. This rule applies to anything that flows, spreads, or sprays: shampoo, conditioner, lotion, toothpaste, deodorant, sunscreen, peanut butter, yogurt, and jam all count.

The bag itself must be removed and placed in the security bin during screening, so pack it where you can reach it easily. If a container is larger than 3.4 ounces, it cannot go in your carry-on, even if it is not full. Solid items like bar soap, solid deodorant, or a stick of lip balm do not count as liquids and do not need to go in the bag.

Some items are restricted entirely from carry-on bags regardless of size: flammable liquids (like lighter fluid), certain aerosols, and compressed gases. If you are unsure whether something is allowed, the TSA website has a searchable tool where you can type the item name and get a yes-or-no answer.

Key Takeaways

  • Liquids, gels, and aerosols must be 3.4 ounces or smaller and fit in one clear quart-sized bag; anything larger stays in checked luggage.
  • Solid items like bar soap, solid deodorant, and toothpaste tablets do not count as liquids and can be packed normally.
  • Electronics larger than a laptop (like a full-sized printer or power tools) are prohibited in carry-on bags.
  • Sharp objects and tools that could be used as weapons—including box cutters, ice picks, and most knives—cannot go in carry-on but are allowed in checked bags.
  • Medications in original labeled containers and medical devices like inhalers and EpiPens are allowed in carry-on bags without size limits.

Clothing, Shoes, and Personal Items

Clothing and shoes have no restrictions and take up most of a typical carry-on bag. Pack what you need for your trip, keeping in mind that carry-on space is limited. A standard carry-on roller bag holds roughly what a large suitcase would, but you also need room for items you will remove during security screening (shoes, belt, jacket) and anything you want to access during the flight.

Accessories like scarves, hats, belts, and jewelry are fine. Underwear, socks, and hosiery are fine. If you are traveling with a baby, diapers and baby clothes pack normally. Wet or damp clothing is allowed but will take up space and may drip on other items.

Electronics and Chargers

Laptops, tablets, e-readers, phones, and their chargers are allowed in carry-on bags. You will need to remove your laptop and place it in a separate security bin during screening, so pack it where you can reach it. Larger electronics like full-sized printers, power tools, or gaming consoles are not allowed in carry-on bags and must go in checked luggage if you need to bring them.

Portable battery packs (power banks) are allowed in carry-on bags, but lithium battery packs have limits: you can bring one spare lithium battery or battery pack per person. Batteries must be in carry-on only, not checked luggage, because of fire risk. If you are unsure whether a battery pack meets the size limit, check the watt-hour rating on the label—it should be 100 watt-hours or less.

Food and Drinks You Can Bring

Solid foods are allowed in carry-on bags with no restrictions: sandwiches, fruit, nuts, granola bars, cookies, cheese, and crackers all travel fine. Liquids and gels count as the 3-1-1 rule, so peanut butter, yogurt, jam, honey, and hummus must be 3.4 ounces or smaller and fit in your liquids bag.

You cannot bring beverages through security—water bottles, juice, coffee, and milk must be empty when you pass through the checkpoint. You can fill a water bottle at a fountain or buy a drink after security. Frozen items like ice packs are allowed only if they are completely solid when you go through screening; if they have any liquid or slush, they will be confiscated.

Medications and Medical Devices

Prescription and over-the-counter medications in their original labeled containers are allowed in carry-on bags without size or quantity limits. Bring them in their pharmacy bottles with your name on the label. Inhalers, EpiPens, and other medical devices do not count toward your liquids limit and do not need to be in the quart-sized bag.

If you carry syringes or needles for diabetes or another condition, pack them in a clear plastic bag and declare them to security. Liquid medications like insulin are allowed in carry-on bags and do not count toward the 3-1-1 limit, but it is a good idea to keep them in a separate bag and let the officer know you have them. If you travel with medical equipment like a CPAP machine or oxygen concentrator, contact your airline before your trip to confirm their rules.

Items That Are Prohibited in Carry-On Bags

Sharp objects and tools cannot go in carry-on: this includes kitchen knives, box cutters, ice picks, razors, scissors with blades longer than 4 inches, and most multi-tools. These items are allowed in checked luggage. Sporting equipment like baseball bats, hockey sticks, ski poles, and golf clubs are also prohibited in carry-on but allowed in checked bags.

Firearms, ammunition, and explosives are prohibited entirely on passenger aircraft. Lighters and lighter fluid are prohibited in both carry-on and checked bags. Flammable liquids, paints, and certain cleaning products cannot go in carry-on bags. Realistic toy guns and replica firearms are prohibited because they can be mistaken for real weapons during security screening.

Self-defense items like pepper spray, brass knuckles, and stun guns are prohibited in carry-on bags. Pepper spray is allowed in checked luggage only if it has a safety mechanism and is equipped with less than 2 percent by mass of tear gas (CS or CN). If you are unsure about a specific item, the TSA website has a searchable database where you can type the object and get an when ready answer.

Packing Strategy to Maximize Space

Carry-on bags are smaller than checked bags, so packing efficiently matters. Roll clothes instead of folding them to save space. Put heavier items like shoes and electronics at the bottom of the bag, near the wheels if it is a roller. Use the pockets and compartments for small items like socks, chargers, and medications.

Pack items you will need during the flight or when ready after landing in the top or front pocket: phone charger, medications, a change of clothes, toiletries, and any documents. This way you do not have to dig through the entire bag at your destination. If you are checking a bag as well, pack a full outfit and basic toiletries in your carry-on in case your checked bag is delayed.

Frequently Asked Questions

Can I bring a full-size bottle of shampoo if I only use a little bit?

No. The rule is based on container size, not how full it is. Any container larger than 3.4 ounces cannot go in carry-on, even if it is nearly empty. You can buy travel-sized bottles at drugstores, or transfer shampoo into a small container before your trip.

Are solid deodorant and toothpaste allowed in carry-on?

Solid deodorant is allowed without limits. Toothpaste is a gel and must be 3.4 ounces or smaller and fit in your liquids bag. Toothpaste tablets or solid toothpaste bars are allowed without limits.

What happens if I accidentally pack something prohibited?

Security will find it during screening and confiscate it. You will not be charged or fined, but you will lose the item. If you realize before you reach security that you have something prohibited, you can go back and check it or throw it away.

Can I bring my laptop through security without removing it?

Requirements vary by airport and security lane. Some airports have newer screening technology that allows laptops to stay in bags; others require removal. Remove your laptop and place it in a bin to be safe, unless signs at your airport say otherwise.

Is a power bank allowed if it is very large?

Power banks are allowed in carry-on only, not checked luggage. Most standard power banks are fine, but if yours is larger than 100 watt-hours, it is prohibited. Check the label on your power bank for the watt-hour rating.