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Keep This Handy: Carry-On Sizing Requirements for Every US Airline
Never again show up nervous that your bag is too big.
When preparing for air travel within the United States, one of the most important details to consider is carry-on luggage size. While most major U.S. airlines follow similar guidelines, there are enough variations to trip up an unsuspecting traveler. Whether you’re flying budget or full-service, understanding the specifics can help you avoid surprise fees and boarding delays.
Infographic: Matador Network
Breaking down what these dimensions mean
Most legacy carriers—including American Airlines, Delta Air Lines, United Airlines, and Alaska Airlines—adhere to a standard carry-on size of 22 x 14 x 9 inches. This includes handles and wheels. These dimensions are designed to ensure the bag fits in the overhead bins and complies with Transportation Security Administration (TSA) expectations.
In addition to the carry-on, passengers are generally allowed one personal item, such as a backpack, purse, or laptop bag. These personal items must fit under the seat in front of you. Airlines like United and American specify personal item dimensions—often around 17 x 10 x 9 inches—while others simply state that it must fit under the seat.
Budget airlines frequently have their own rules, however. Low-cost carriers such as Spirit, Frontier, and Allegiant differ significantly from the legacy players like United and Delta. While their carry-on size allowances can be slightly larger—24 x 16 x 10 inches in many cases—these bags are not included in the base fare. Only a personal item is free, and exceeding those limits typically triggers additional fees. For example, Spirit allows personal items up to 18 x 14 x 8 inches, but charges for anything larger. Note that Southwest recently did away with its free checked baggage policy, so following the airline’s carry-on policy is more important than ever.
JetBlue recently updated its policy to include a full-size carry-on in its Blue Basic fare—something it had previously excluded. This change, effective from September 2024, brings them in line with other full-service carriers. Sun Country Airlines, meanwhile, includes carry-on bags in upgraded fare classes only, and imposes a 35-pound weight limit—something rarely enforced by other carriers. 
