The TSA rules for carry-on bags are simpler than most people think

You can bring a carry-on bag onto the plane as long as it fits in the overhead bin or under the seat in front of you. The TSA (Transportation Security Administration) does not limit what you pack inside it by weight or total volume — only by what the item is. Liquids, gels, and aerosols follow a strict rule: 3.4 ounces or 100 milliliters per container, and all containers must fit inside a single quart-sized clear plastic bag. Everything else — clothes, electronics, books, shoes — travels freely as long as the bag itself meets your airline's size limits.

Your airline, not the TSA, sets the actual carry-on dimensions. Most major carriers allow a bag up to 22 inches long, 14 inches wide, and 9 inches deep, but some budget airlines are stricter. Check your airline's website before you pack, because a bag that fits on one airline may be gate-checked on another.

Key Takeaways

  • Liquids, gels, and aerosols are limited to 3.4 ounces per container, and all containers must fit in one quart-sized clear plastic bag.
  • Electronics like laptops, phones, and tablets can go in your carry-on, but you will remove them at security screening.
  • Knives, razors, lighters, and tools with blades or sharp points are prohibited in carry-on bags but may be allowed in checked luggage.
  • Your airline sets the size limit for carry-on bags, so check their website — a bag that fits on one airline may be rejected on another.
  • Medications in solid form (pills, tablets) and medical devices like inhalers and EpiPens travel freely in carry-on bags.

Liquids, gels, and aerosols: the 3-1-1 rule

The TSA's liquid rule applies to anything that flows, spreads, or sprays. This includes shampoo, conditioner, lotion, toothpaste, deodorant, mascara, lip gloss, peanut butter, yogurt, honey, and spray sunscreen. Each container can hold no more than 3.4 ounces (100 milliliters). You can bring multiple containers as long as each one is under the limit.

All your liquid containers must fit inside a single quart-sized clear plastic bag — the kind you can buy at any drugstore or get free at airport security. You remove this bag from your carry-on at the security checkpoint and place it in the bin with your shoes and electronics. If even one container is over 3.4 ounces or if your containers do not fit in the quart bag, the entire bag will be confiscated.

Solid items that look like liquids are allowed: solid deodorant, solid perfume, lip balm, and solid sunscreen all pass through security. Frozen items are permitted if they are completely solid when you go through the checkpoint, but TSA officers may confiscate them if they have started to thaw.

Electronics and chargers you can bring

Laptops, tablets, e-readers, phones, cameras, and portable chargers all go in your carry-on. You will remove your laptop and any device larger than a phone at security screening and place it in a separate bin. Smaller electronics like phones and earbuds stay in your bag. Once you are past security, you can use these devices throughout the airport and on the plane, though the airline may ask you to put them in airplane mode during flight.

Charging cables and power adapters are fine. Portable battery packs (power banks) are allowed, but they must have a capacity of 100 watt-hours or less. Most standard portable chargers fall well under this limit. Spare lithium batteries are prohibited in carry-on bags, so if you have a backup battery for a camera or other device, it must go in checked luggage.

Headphones, smartwatches, and fitness trackers travel freely. If you use a CPAP or other medical device that requires power, bring the device and its power cord in your carry-on — you will not have to remove it at security.

What is banned from carry-on bags

Sharp objects and tools are prohibited: kitchen knives, box cutters, razors, scissors with blades longer than 4 inches, and ice picks cannot go in your carry-on. Lighters and lighter fluid are also banned. Firearms, ammunition, and explosives are prohibited. Sporting equipment with sharp edges — like ski poles, ice skates, or spear guns — must be checked.

Some items are banned from both carry-on and checked bags. These include self-defense sprays (pepper spray, mace), flares, and certain types of lighters. Lithium batteries in excess of 100 watt-hours are prohibited in both carry-on and checked luggage on passenger planes.

Certain tools and equipment are allowed in checked bags but not carry-on: hammers, wrenches, pliers, saws, and screwdrivers can be checked. If you need these items at your destination and do not want to check a bag, you can buy them after you arrive or rent them locally.

Medications and medical devices

Prescription medications in pill or tablet form travel freely in your carry-on in their original labeled containers. You do not need to declare them at security unless the TSA officer asks. Liquid or gel medications like inhalers, EpiPens, and insulin are allowed and do not count toward your 3.4-ounce liquid limit — pack them separately from your quart bag of toiletries.

Medical devices like CPAP machines, glucose monitors, and oxygen concentrators are permitted. Syringes are allowed if they are accompanied by medication or a medical device. If you use injectable medications, bring them in their original containers with your name on the label.

Over-the-counter medications in solid form (ibuprofen, acetaminophen, allergy tablets) are allowed. Liquid or gel versions of these medications follow the standard liquid rule and must fit in your quart bag.

Food and drinks you can bring through security

Solid foods are allowed: sandwiches, fruit, vegetables, cheese, crackers, cookies, and candy all pass through security. You can bring a full meal if you want. Peanut butter, hummus, jam, and other spreads are considered liquids or gels and must follow the 3.4-ounce rule.

You cannot bring liquids or gels through security, including water, juice, yogurt, soup, or peanut butter. However, you can buy a bottle of water, juice, or other beverage after you pass through security and bring it onto the plane. Many airports have water fountains and refill stations past the checkpoint.

Alcohol is prohibited in carry-on bags. You can purchase duty-free alcohol in the airport after security and bring it onto the plane, but it will be sealed and you cannot open it during the flight.

Clothing, shoes, and personal items

There are no restrictions on clothing, shoes, belts, or accessories. Pack as much as your carry-on bag can hold. Jackets, sweaters, and coats can stay in your bag or be worn onto the plane. Hats, scarves, and gloves are fine.

Jewelry, watches, and eyeglasses are allowed. You do not need to remove them at security unless they trigger the metal detector. Wallets, keys, and phones stay with you through the checkpoint.

Books, magazines, notebooks, and pens are permitted. Laptops and tablets are allowed but must be removed at security screening. Umbrellas are allowed in carry-on bags.

Items that depend on your airline or destination

Some items are allowed by the TSA but may be restricted by your airline or the country you are traveling to. Sporting equipment like golf clubs, tennis rackets, and fishing rods are usually allowed in carry-on if they fit, but some airlines require them to be checked. Contact your airline before you pack.

If you are traveling internationally, the rules of your destination country explore. Some countries prohibit certain foods, plants, or animal products. Check the customs rules for your destination before you pack. Items that are legal in the United States may be illegal where you are going.

Duty-free items purchased at the airport can be brought onto the plane in their sealed bag, even if they would normally be prohibited in carry-on luggage. Keep the receipt and the sealed bag together.

Frequently Asked Questions

Can I bring a full-size bottle of shampoo if I check my bag?

Yes. Checked luggage has no restrictions on liquids, gels, or aerosols. You can pack full-size bottles of shampoo, conditioner, lotion, and other toiletries in your checked bag. Make sure containers are sealed to prevent leaks that could damage other items.

What if my carry-on bag is slightly larger than my airline's size limit?

The airline can gate-check your bag at no charge if it does not fit in the overhead bin or under the seat. This means your bag goes into the cargo hold with checked luggage but you do not pay a checked bag fee. Arrive early so you have time to gate-check if needed, and keep valuables and electronics with you.

Can I bring a lighter in my checked bag?

Most lighters are prohibited in both carry-on and checked bags. However, one disposable lighter or one lighter with fuel inside a protective case may be allowed in checked luggage only — check with your airline before packing. Lighter fluid is always prohibited.

Do I need to declare my medications at security?

You do not need to declare solid medications like pills or tablets. For liquid or gel medications like inhalers or insulin, keep them in their original labeled containers and have them easily accessible at security. The TSA officer may ask about them, but you do not need to volunteer the information.

Can I bring an empty water bottle through security and fill it after?

Yes. Empty water bottles, coffee cups, and other containers are allowed through security. Many airports have water fountains and refill stations past the checkpoint where you can fill your bottle for free before boarding.