Carry-on bags have strict size limits that airlines enforce at the gate

Most airlines allow one carry-on bag and one personal item (purse, backpack, or laptop bag) in the cabin. The carry-on bag must fit in the overhead bin, which is typically 22 inches long, 14 inches wide, and 9 inches tall — though this varies slightly by airline. If your bag is larger than that, you will have to check it at the gate, and you may pay a fee.

The personal item is smaller and goes under the seat in front of you. Airlines measure carry-on bags at check-in and the gate, so a bag that barely fits at one airline may not fit at another. If you are flying multiple airlines or want to avoid surprises, buy a bag that is clearly smaller than the standard overhead bin — 20 inches by 13 inches by 8 inches is a safe choice.

Weight limits for carry-on bags are less common than size limits, but some airlines do enforce them. Check your airline's website before you pack, because the rules differ between carriers and sometimes between ticket classes on the same airline.

Checked bags usually cost money and have their own size and weight rules

Most airlines include one free checked bag with a standard ticket, but budget carriers like Spirit and Frontier charge for any checked luggage. A checked bag typically cannot exceed 62 inches in total dimensions (length plus width plus height) and must weigh no more than 50 pounds. Bags larger or heavier than that incur oversize or overweight fees, usually $100 to $200 per bag.

If you are checking two bags, the second one almost always costs extra — usually $35 to $50 on domestic flights, more on international routes. A third checked bag is rarely worth the fee unless you are moving or traveling for an extended stay. Measure and weigh your bags before you go to the airport; scales at home are more accurate than the ones at check-in, and you will have time to repack if needed.

Checked bags take longer to arrive than you do. On a short flight, your bag may not be waiting when you land. On a connection, your bag may not make the flight with you. If you need something during your trip, do not pack it in a checked bag.

Key Takeaways

  • Carry-on bags must fit in the overhead bin, typically 22 by 14 by 9 inches, and airlines measure them at the gate.
  • You can bring one carry-on bag and one personal item (purse, backpack, or laptop bag) into the cabin without paying extra.
  • Checked bags usually cost money on budget airlines and have a 62-inch total dimension limit and 50-pound weight cap.
  • Most airlines include one free checked bag with a standard ticket, but a second bag costs $35 to $50 on domestic flights.
  • Checked bags arrive after you do, so pack items you need during your trip in your carry-on instead.

Prohibited items explore to both carry-on and checked bags, with some exceptions

The Transportation Security Administration (TSA) maintains a list of items you cannot bring on a plane at all. Weapons, explosives, and flammables are banned from both carry-on and checked bags. Lighters, matches, and aerosol cans are prohibited in carry-on bags but allowed in checked bags in limited quantities. Lithium batteries (the kind in laptops and power banks) are allowed in carry-on bags but restricted in checked bags.

Liquids, gels, and aerosols in carry-on bags are limited to 3.4 ounces per container, and all containers must fit in a single quart-sized plastic bag. Toothpaste, shampoo, lotion, and peanut butter all count as liquids under this rule. You can pack these items in checked bags without the size limit, so if you travel with full-sized bottles, check them instead.

The TSA website has a searchable tool where you can look up specific items. If you are unsure whether something is allowed, search for it before you pack. Confiscation at security is common and happens to items people thought were fine.

International flights have additional restrictions on what you can bring

Countries outside the United States have their own rules about what can enter. Some countries ban certain foods, plants, and animal products. Others restrict the amount of currency you can bring or require you to declare it. If you are traveling internationally, check the customs rules for your destination country before you pack.

The airline you are flying may also have stricter rules than the TSA for international routes. Some airlines do not allow certain items in checked bags on flights to specific countries. Call the airline or check their website if you are packing anything unusual — food, tools, sporting equipment, or anything that could be considered a weapon.

Oversized items like sports equipment and musical instruments need advance notice

Skis, surfboards, golf clubs, and bicycles do not fit in a standard checked bag. Most airlines allow these items but charge an oversized baggage fee, usually $50 to $150 per item. Some airlines require you to notify them in advance, and a few have specific rules about how items must be packed (a bicycle may need to be in a bike bag, for example).

Musical instruments can sometimes travel as a carry-on if they fit in the overhead bin or under the seat. A full-sized guitar or cello will not fit, so you will need to check it. Hard cases protect instruments better than soft cases, and some musicians buy a seat for a valuable instrument instead of checking it. Call the airline before you travel if you are bringing an instrument.

Packing your carry-on strategically saves time and stress at security

Put items you need during the flight in your personal item, not your carry-on. Your personal item stays with you; your carry-on goes in the overhead bin and you may not reach it until you land. Electronics, medications, valuables, and a change of clothes should go in your personal item.

Pack your carry-on so that nothing fragile is on the bottom. Overhead bins get slammed shut, and bags shift during flight. Soft items like clothes and towels work well on the bottom; hard items and anything breakable should be on top or in the middle.

At security, have your ID and boarding pass ready before you reach the checkpoint. Remove your laptop, liquids bag, and shoes before you reach the scanner. These small steps move the line faster and reduce the chance that a TSA officer will need to search your bag.

Frequently Asked Questions

Can I bring a full-sized suitcase as a carry-on?

Only if it fits in the overhead bin. Most full-sized suitcases are too large. Measure your suitcase before you travel, or bring it to the airport early to test it against the sizing frame at the ticket counter. If it does not fit, you will have to check it and pay a fee if it is not your first checked bag.

What happens if my bag is overweight at the airport?

You will be charged an overweight fee, usually $50 to $100 per bag depending on how much over 50 pounds it is. You can ask to repack items into your carry-on or another bag if you have time, but the airline is not required to let you. Weigh your bags at home to avoid this surprise.

Can I bring a power bank or portable charger on the plane?

Yes, in your carry-on bag only. Lithium batteries are allowed in carry-on bags but restricted or banned in checked bags because of fire risk. Most portable chargers are under 100 watt-hours, which is the TSA limit. Check your charger's specifications if you are unsure.

Do I have to pay extra if I bring a backpack as my personal item?

No. One personal item is included with your ticket. A backpack, purse, laptop bag, or small daypack all count as a personal item and do not cost extra. You get one personal item and one carry-on bag at no additional charge.

Can I bring food through security?

Solid foods like sandwiches, fruit, and snacks can go through security and into your carry-on. Liquids and gels like peanut butter, yogurt, and honey are subject to the 3.4-ounce liquid rule. Pack these items in your checked bag if you want to bring full-sized containers.