Even if you have your packing strategy down to a science, you’ve probably had at least one run-in with a bulging carry-on bag that won’t fit into the overhead bin as a flight attendant glares at you. Even worse, you may have been forced to gate check when your hard-case roller didn’t fit snugly in the dreaded measurement box. Did the airline website understate how seriously gate agents would take size limits, or did you flat-out forget to check?
To add to the confusion, restrictions vary by airline and even ticket class—meaning that suitcase you seamlessly brought on board for one flight might be gate checked on another. Before your next flight, use this guide to make sure your bag will fit in the overhead compartment.
What size should your carry-on luggage be?
On domestic flights within the United States, a carry-on bag that’s smaller than 22 x 14 x 9 inches (45 linear inches), including handles and wheels will meet the size restrictions of all major airlines, such as United Airlines and Alaska Airlines. Although some airlines, notably Southwest and Spirit Airlines, will allow a bag up to 50 linear inches, it’s a good idea to look for a bag that’s around 45 linear inches or smaller if you’re shopping for a new carry-on (and will likely use it on multiple different airlines).
The size limit varies more widely on non-U.S. airlines, but unless you’re flying on say, a small island-hopper in the Azores, 45 linear inches or smaller will allow you to meet the requirements of just about all of them.
Weight limits for carry-on luggage
Aside from Frontier and Hawaiian Airlines, the major U.S. airlines do not have a weight limit for carry-on bags. However, they generally require travelers to be able to lift their bags into the overhead compartment (or, for anyone assisting the elderly or persons with disabilities).
Outside the U.S., however, most airlines have a weight limit for carry-on bags. They can range anywhere from 11 pounds (China Southern) to 51 pounds (British Airways). Many budget airlines, both domestic and international, have strict guidelines for the number and size of carry-on baggage—and enforce them—so be sure to check your specific airlines’ requirements when traveling abroad.
Carry-on sizes for major domestic airlines (United States)
The carry-on restrictions are for a standard, economy ticket. Some airlines allow additional carry-ons, a larger bag, or a bag that weighs more than the standard economy weight if you have booked a premium economy, business, or first-class ticket.
Carry-on sizes for major international airlines (United States)
How many carry-ons can you bring?
Most major domestic and international airlines allow economy passengers one carry-on and one personal item. (Business- or premium-class passengers are usually allowed more.) Basic economy tickets typically allow one personal item but no use of the overhead bin compartments.
Carry-on versus personal item
A personal item must fit under the seat in front of you. Purses, small handbags and backpacks, briefcases, and laptop backpacks and bags usually make the cut. Some airlines allow diaper bags, cameras, and duty-free merchandise—or items purchased within the airport—in addition to a carry-on and personal item.
How to measure your carry-on luggage
To calculate the size of your carry-on bag, measure the length, height, and depth (or width) of your bag. You can add the three numbers together to find the total linear inches. For example, a bag with a length of 20 inches, width of 12 inches, and depth of 6 inches would be 20+12+6 = 38 linear inches.
If you don’t have a measuring tape handy, you can also find the dimensions of your bag on the seller’s product page online (either before or after buying it) under the product specifications.
What counts as a carry-on?
Generally, a small rolling suitcase, duffel bag, or larger backpack will count as a carry-on bag. Garment bags count as carry-ons, as long as they follow the dimensions specified by the airline. For instance, American Airlines allows passengers to carry on a soft-sided garment bag up to 51 inches in lieu of a standard piece of luggage.
By law, airlines are required to allow passengers to substitute a small musical instrument for a carry-on bag as long as it fits under the seat or in the overhead compartment. Travelers may want to choose a preboarding option to ensure there is space for the instrument, which is not guaranteed.
Travelers can purchase a seat for larger instruments (such as a cello), as long as the instrument adheres to the airline’s size and weight guidelines. Military bags and sports equipment are also allowed as carry-on luggage, although bigger equipment—such as surfboards, golf clubs, and hockey gear—may be charged the standard checked baggage fee, depending on the airline.
What can you pack in your carry-on and personal item?
Carry-on luggage must pass through airport security and, therefore, cannot include dangerous materials or excessive amounts of liquid. According to the TSA’s 3-1-1 liquids rule, they can be a maximum of 3.4 ounces (100 ml) per item, they must fit into a quart-sized plastic bag, and each passenger is allowed one quart-sized bag.
In general, food is allowed in your carry-on, though some items (such as yogurt) may be subject to the TSA’s liquids restrictions—just like your toothpaste.
Carry-on luggage cannot contain cutting instruments, explosives, or flammable materials, though some of these prohibited items are allowed in checked bags. If you have any doubt about a specific item, the TSA’s What Can I Bring? tool is a helpful resource to consult.
This article was originally published in 2019 and most recently updated on August 11, 2022, to include updated information.