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

The single biggest restriction on carry-on bags 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 can bring only one bag per person. This rule applies to the TSA and most international carriers.

Common items that count as liquids or gels include shampoo, conditioner, lotion, toothpaste, deodorant, sunscreen, peanut butter, yogurt, and jam. Solid deodorant is allowed in unlimited quantities. Aerosols like hairspray and spray deodorant follow the same 3.4-ounce limit. Medications in liquid or gel form (like liquid ibuprofen) are exempt from the 3.4-ounce limit but must be declared to the TSA officer at security.

Key Takeaways

  • Liquids, gels, and aerosols must each be 3.4 ounces or smaller and fit in one quart-sized clear bag.
  • Solid foods, books, electronics, and most clothing have no restrictions and can fill your carry-on to its weight limit.
  • Sharp objects like box cutters, razors, and most knives are prohibited, but safety razors and electric shavers are allowed.
  • Lighters, flammables, and tools larger than 7 inches are banned from carry-on bags but may be allowed in checked luggage.
  • Batteries, power banks, and electronic devices must follow specific rules: lithium batteries are limited, and large power banks may be restricted.

Electronics and Power Sources

You can bring laptops, tablets, phones, cameras, and headphones in your carry-on without restriction. Remove your laptop and large electronics from your bag at security screening. Power banks and portable chargers are allowed, but lithium battery power banks larger than 100 watt-hours (Wh) are prohibited in both carry-on and checked bags. Most standard phone chargers and small power banks fall well under this limit.

Spare lithium batteries (the kind you might carry for a camera or electronic device) are prohibited in carry-on bags but may be allowed in checked luggage under specific conditions—check with your airline before packing them. Rechargeable batteries in devices you plan to use are fine. Extension cords, USB cables, and charging blocks have no restrictions.

Food, Drinks, and Solid Items

Solid foods pass through security with no restrictions: sandwiches, fruit, vegetables, cheese, chocolate, cookies, and nuts are all allowed. You cannot bring liquid or gel foods through security, but you can purchase beverages after you clear the checkpoint. If you freeze a gel or liquid food solid (like a frozen juice box), it may be allowed through security, though TSA officers have final say at each checkpoint.

Books, magazines, documents, and printed materials have no carry-on limits. Clothing, shoes, belts, and accessories are unrestricted. Sports equipment like tennis rackets, golf clubs, and ski poles are allowed but count toward your carry-on size and weight limits—check your airline's specific dimensions and weight allowance before packing.

Prohibited Sharp Objects and Tools

Box cutters, utility knives, and most kitchen knives are prohibited in carry-on bags. Pocket knives, multi-tools with blades, and scissors with blades longer than 4 inches are also banned. Safety razors and electric shavers are allowed. Straight razors are prohibited.

Tools longer than 7 inches are not allowed in carry-on bags. This includes screwdrivers, wrenches, hammers, and pliers. Smaller tools like a 6-inch screwdriver or adjustable wrench may be allowed—the 7-inch rule is a guideline, and TSA officers make the final decision. If you need tools for your trip, pack them in checked luggage instead.

Lighters, Flammables, and Restricted Items

Lighters are prohibited in both carry-on and checked bags with very few exceptions. You cannot bring matches, lighter fluid, or other flammable liquids. Aerosol cans of spray paint, insecticide, or cooking spray are prohibited in carry-on bags and severely restricted in checked luggage.

Firearms, ammunition, and explosives are prohibited. Realistic toy guns and replica weapons may be confiscated or cause delays at security. Fireworks, flares, and sparklers are banned. Corrosive materials like bleach and drain cleaner are prohibited. If you are unsure whether an item is allowed, check the TSA website or contact your airline before you pack.

Medications and Medical Equipment

Prescription and over-the-counter medications in solid form (pills, tablets, capsules) have no restrictions. Liquid medications like cough syrup or liquid ibuprofen are exempt from the 3.4-ounce limit but should be declared to the TSA officer at security. Bring medications in their original labeled containers when possible.

Medical devices like inhalers, EpiPens, and insulin pumps are allowed. Syringes and needles used for medical purposes are permitted if they are accompanied by medication or a medical device. Mobility aids like canes, crutches, and walkers are allowed. CPAP machines and other medical equipment are permitted in carry-on bags.

Size and Weight Limits for Your Airline

The TSA does not set a universal size or weight limit for carry-on bags—each airline sets its own. Most airlines allow one carry-on bag (typically 22 by 14 by 9 inches) and one personal item like a purse, laptop bag, or backpack. Some airlines charge fees for a second carry-on bag or enforce stricter dimensions for budget fares.

Check your airline's website before you pack to confirm the exact dimensions and weight limit for your ticket type. If your bag is oversized or overweight, you may be forced to check it at the gate, which can delay your boarding. Arriving early gives you time to repack if needed.

Frequently Asked Questions

Can I bring a full-size bottle of shampoo if I transfer it to a smaller container?

No. The 3.4-ounce limit applies to the container you bring through security, not the original bottle. You must use a container that holds 3.4 ounces or less. You can purchase full-size bottles after you clear security or pack them in checked luggage.

Are gel insoles and gel ice packs allowed in carry-on bags?

Gel insoles and gel shoe inserts are typically allowed because they are worn or used as part of clothing or footwear. Gel ice packs are usually prohibited because they are considered gels under the 3-1-1 rule. If the ice pack is completely frozen solid, it may be allowed, but TSA officers have final say at each checkpoint.

Can I bring a lighter if I don't plan to use it on the plane?

No. Lighters are prohibited in carry-on bags regardless of intent. The only exception is a single lighter without fuel in a protective case, which some airlines allow in checked luggage only—check with your airline first.

What happens if I accidentally pack a prohibited item?

TSA officers will confiscate the item at security. You will not be charged a fine, but you will lose the item. If you realize before you reach security, you can leave the item at home, mail it, or ask a companion to take it back.

Are phone chargers and USB cables restricted?

No. Phone chargers, USB cables, charging blocks, and extension cords are allowed in unlimited quantities in carry-on bags. They have no size or weight restrictions.