The TSA's Basic Rules for Carry-On Items

The Transportation Security Administration (TSA) allows most everyday items in your carry-on bag, but liquids, gels, and aerosols follow a strict rule: containers must be 3.4 ounces (100 milliliters) or smaller, and all containers must fit inside a single quart-sized clear plastic bag. Electronics larger than a laptop, weapons of any kind, and sharp objects longer than 7 inches are prohibited. Everything else — clothing, books, toiletries in small containers, food that is not liquid or gel — generally passes through security.

The rules exist because the TSA screens carry-on bags before they board the plane, while checked luggage goes through different screening after you drop it off. What matters most is that you pack items the screener can see clearly and that pose no safety risk in the cabin. If you are unsure about a specific item, the TSA website has a "What Can I Bring?" tool where you can search by object name.

Key Takeaways

  • Liquids, gels, and aerosols in containers larger than 3.4 ounces must go in checked luggage, and all small containers must fit in one quart-sized plastic bag.
  • Sharp objects like knives, box cutters, and scissors with blades longer than 7 inches are prohibited in carry-on bags but allowed in checked luggage.
  • Electronics including laptops, tablets, and cameras are allowed in carry-on bags and must be removed at security for screening.
  • Food that is solid — sandwiches, fruit, snacks — is allowed through security, but peanut butter, honey, and other spreads are treated as liquids and must be 3.4 ounces or smaller.
  • Medications in their original labeled containers are allowed in carry-on bags in any quantity, even if they exceed the 3.4-ounce limit.

Liquids, Gels, and Aerosols: The 3-1-1 Rule

The 3-1-1 rule is the single most important thing to remember: 3.4 ounces per container, 1 quart-sized bag, 1 bag per passenger. This applies to toothpaste, shampoo, conditioner, lotion, sunscreen, deodorant, mascara, liquid foundation, lip gloss, peanut butter, yogurt, jam, honey, and anything else that flows, spreads, or sprays. If the product is thicker than water but still moves when you tilt the container, it counts as a gel or liquid.

You can bring multiple containers as long as each one is 3.4 ounces or smaller and they all fit inside the bag without forcing the zipper. The bag itself must be clear so the screener can see inside without opening it. You can buy a pre-made TSA-approved bag at most drugstores and airports, or use any clear quart-sized freezer bag. Medications and medical devices like inhalers or EpiPens are exempt from the 3.4-ounce limit and do not need to go in the bag.

Electronics and Chargers You Can Bring

Laptops, tablets, e-readers, phones, cameras, and portable chargers all go in your carry-on. You will need to remove your laptop and any device larger than a tablet from your bag at security so it can be scanned separately. Smaller electronics like phones and earbuds can stay in your bag. Power cords and charging cables have no restrictions.

Lithium batteries are the reason electronics get special attention. Spare lithium batteries — the kind you might pack as backups — are prohibited in carry-on bags and checked luggage on passenger planes. However, batteries installed inside devices like laptops and phones are allowed. If you need to travel with spare batteries, contact your airline before you book, as some carriers have exceptions for certain battery types.

Food and Beverages: What Passes Security

Solid food passes through security with no restrictions. You can bring sandwiches, fruit, vegetables, cheese, crackers, cookies, chocolate, and nuts in your carry-on. Once you clear security, you can also buy beverages inside the airport and bring them onto the plane. Any liquid food — soup, yogurt, peanut butter, jam, honey, or sauces — must follow the 3-1-1 rule and fit in your quart-sized bag in containers of 3.4 ounces or smaller.

Frozen items are allowed if they are completely solid when you go through security, but they will thaw during the flight and become liquid, which means they could leak into your bag. Pack them in a waterproof container or checked luggage instead. Baby food and breast milk are exempt from the 3-1-1 rule and can be brought in any quantity, even if they exceed 3.4 ounces.

Sharp Objects and Tools: Carry-On Versus Checked

Knives, box cutters, razors, and scissors with blades longer than 7 inches are prohibited in carry-on bags. Scissors with blades 7 inches or shorter are allowed. Nail clippers, nail files, and tweezers are permitted. Tools like screwdrivers, wrenches, and hammers are prohibited in carry-on but allowed in checked luggage. If you are traveling with tools for work or a hobby, pack them in your checked bag instead.

The rule applies to the blade or cutting edge itself, not the total length of the object. A 6-inch knife is allowed; a 7.5-inch knife is not. If you are unsure about a specific item, ask the TSA at security before you unpack your bag — screeners can tell you whether it will pass or needs to go in checked luggage.

Items Completely Prohibited on Planes

Firearms, ammunition, explosives, flammable liquids, and certain chemicals are prohibited in both carry-on and checked luggage. Realistic toy guns and replica weapons are also banned from carry-on bags. Lighters are prohibited in carry-on but one lighter is allowed in checked luggage if it has a safety case. Matches are prohibited in both carry-on and checked bags.

Self-defense items like pepper spray and tasers 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. Sporting equipment like baseball bats, hockey sticks, and ski poles are prohibited in carry-on but allowed in checked bags. If you have a question about whether a specific item is allowed, the TSA website search tool or a call to your airline can give you a definitive answer before you pack.

International Flights and Airline-Specific Rules

International flights follow the same TSA rules for U.S. departures, but the destination country may have different rules for what you can bring into that country. Some countries prohibit certain foods, plants, or medications. Check the customs rules for your destination before you pack. If you are flying out of an international airport or to a country outside the U.S., contact your airline or the destination country's customs office to confirm what is allowed.

Individual airlines also set their own carry-on size and weight limits, which are stricter than TSA rules. A bag that passes TSA screening might be too large for your airline's overhead bin. Check your airline's website for carry-on dimensions and weight limits before you travel. Some airlines charge fees if your carry-on is oversized or if you bring a second personal item.

Frequently Asked Questions

Can I bring a full-size bottle of shampoo if I pack it in checked luggage?

Yes. The 3-1-1 rule applies only to carry-on bags. You can pack full-size bottles of shampoo, lotion, sunscreen, and other liquids in your checked bag with no restrictions on size. Make sure bottles are sealed and consider packing them in a waterproof bag in case they leak during handling.

Are prescription medications allowed in carry-on bags?

Yes. Medications in their original labeled containers are allowed in any quantity in your carry-on bag, even if they exceed 3.4 ounces. Bring a copy of your prescription or a letter from your doctor if the medication is a controlled substance or if the label is not in English. Syringes and inhalers are also allowed.

Can I bring a lighter or matches on a plane?

Lighters and matches are prohibited in carry-on bags. One lighter with a safety case is allowed in checked luggage only. If you smoke, plan to buy cigarettes or a lighter after you arrive at your destination.

What happens if I accidentally pack a prohibited item?

The TSA screener will find it during security screening. You can leave it with the screener, throw it away, or go back to check-in and add it to your checked bag if time allows. You will not be arrested for an honest mistake, but you may miss your flight if the process takes too long.

Do I need to remove my phone and earbuds from my bag at security?

No. Only laptops and devices larger than a tablet need to be removed. Phones, earbuds, and small electronics can stay in your bag during screening.