Standard carry-on dimensions across U.S. airlines
Most U.S. airlines allow carry-on bags measuring 22 inches long by 14 inches wide by 9 inches deep. This is the size limit set by the International Air Transport Association (IATA), and it is what you will see on the websites of American, Delta, United, Southwest, and Alaska Airlines. Some airlines state the limit as 56 centimeters by 36 centimeters by 23 centimeters, which converts to the same measurement.
The actual enforcement of these limits varies. Some airlines measure every bag at the gate; others only measure if a bag looks oversized. If your bag is within the stated dimensions, you should not have a problem, but bags that are close to the limit may be flagged during boarding.
Weight limits for carry-on bags are separate from size limits. Most airlines do not weigh carry-on luggage, but some budget carriers do. Check your specific airline's website before you pack.
Key Takeaways
- The standard carry-on size is 22 by 14 by 9 inches, which most major U.S. airlines use as their official limit.
- Soft-sided bags compress slightly and may fit in overhead bins more easily than hard-sided bags of the same stated dimensions.
- Budget airlines like Spirit and Frontier often have smaller carry-on limits or charge fees for carry-on bags, so verify your airline's rules before packing.
- International airlines may use different size limits, so if you are flying overseas, check the carrier's website rather than assuming the U.S. standard applies.
- Bags that exceed the limit may be gate-checked at no charge, but you lose access to your items during the flight.
How airlines measure carry-on bags
Airlines measure the length, width, and depth of a bag by its outer dimensions. For a rectangular bag, this means measuring the longest point in each direction, including any pockets, wheels, or handles that stick out. A bag with a hard shell is measured as-is; a soft-sided bag is measured when it is fully packed and cannot compress further.
Some airlines use a physical sizer—a metal or plastic frame in the shape of a rectangular box—at the gate to check whether bags fit. If your bag does not fit through the sizer, it will be gate-checked. This is free, but your bag will be loaded into the cargo hold and you will not have access to it during the flight.
The depth measurement is often the one that catches people off guard. A bag that is 22 by 14 inches but 10 inches deep will not fit, even if the first two measurements are correct. Measure all three dimensions before you buy or pack.
Differences between airlines and cabin classes
Most major carriers use the 22-by-14-by-9-inch standard regardless of which cabin you are flying in. However, some airlines offer different allowances for premium cabin passengers. First-class and business-class passengers on international flights sometimes receive larger carry-on allowances, but this is not standard across the industry.
Budget airlines have smaller limits. Spirit Airlines allows carry-on bags of 21.5 by 13.5 by 8.5 inches. Frontier Airlines uses 22 by 14 by 9 inches but charges a fee for carry-on bags unless you are a member of their frequent-flyer program. Allegiant Air charges for carry-on bags as well. If you are flying a budget carrier, check their specific policy before you pack.
Some airlines also distinguish between a personal item and a carry-on bag. A personal item (a purse, backpack, or small bag) usually has no stated size limit and is free. A carry-on bag is larger and counts as your one free carry-on allowance. If you bring both, the personal item goes under the seat in front of you, and the carry-on goes in the overhead bin.
Soft-sided versus hard-sided bags
Soft-sided bags (made of fabric or flexible material) can compress slightly when packed, which sometimes allows them to fit in tight overhead bins even if they are close to the size limit. Hard-sided bags (made of plastic or polycarbonate) do not compress and are measured at their fixed dimensions. If you are concerned about fitting your bag in the overhead bin, a soft-sided bag may give you a small advantage.
Hard-sided bags offer better protection for fragile items and are more durable over time, but they take up more space in the bin. Soft-sided bags are lighter and more flexible, but they offer less protection and can wear out faster if you travel frequently.
Neither type is inherently better—the choice depends on what you are packing and how often you travel. If you pack carefully and stay within the size limit, either type will work.
What happens if your bag is too large
If your bag exceeds the size limit, the airline will gate-check it at no charge. This means your bag will be loaded into the cargo hold with checked luggage and will not be available to you until you land. You will not be able to access anything in the bag during the flight, including medications, electronics, or documents you might need.
Gate-checking is not the same as checking a bag at the ticket counter. You do not pay a checked-bag fee, but you also do not have the option to keep the bag with you. The airline will tag it and load it on the plane.
If you frequently travel with a bag that is borderline in size, consider measuring it against the airline's sizer before you get to the gate. Many airports have sizers displayed near the ticket counter or security checkpoint. If your bag does not fit, you can adjust your packing or check the bag at the counter before boarding begins.
International carry-on size rules
International airlines do not all use the same size limit. European carriers often use the IATA standard of 22 by 14 by 9 inches, but some use slightly different measurements. Asian carriers may have their own limits. If you are flying internationally, check your airline's website for their specific carry-on policy rather than assuming the U.S. standard applies.
Some international airlines are stricter about enforcement than U.S. carriers. If you are connecting through a U.S. airport to an international flight, your carry-on bag must meet both the U.S. airline's limit (if you are flying a U.S. carrier) and the international airline's limit (if you are flying a foreign carrier). When in doubt, choose a bag on the smaller side.
Tips for choosing and packing a carry-on bag
Measure your bag before you buy it, and compare the dimensions to your airline's stated limit. Do not rely on the manufacturer's description—measure the bag yourself with a tape measure. Check the length, width, and depth, and include any wheels or handles that protrude.
When you pack, fill the bag completely so it does not shift or expand during handling. A partially packed bag can shift in the overhead bin and take up more space than necessary. Pack heavier items at the bottom and lighter items on top to keep the bag balanced and easier to lift.
If you are traveling with a bag that is close to the size limit, arrive at the airport early. This gives you time to adjust your packing or check the bag if needed, rather than dealing with it at the gate when the flight is boarding.
Frequently Asked Questions
Can I bring a personal item in addition to my carry-on bag?
Yes. Most airlines allow one personal item (a purse, backpack, laptop bag, or small daypack) in addition to one carry-on bag. The personal item has no stated size limit on most carriers, but it should fit under the seat in front of you. Check your airline's website to confirm, as some budget carriers have different rules.
Do roller bags count toward the carry-on size limit?
Yes. The wheels and handle of a roller bag are included in the size measurement. A roller bag that is 22 by 14 by 9 inches includes the wheels in that measurement, so the actual packing space inside is slightly smaller.
What if my bag fits the length and width but is slightly over 9 inches deep?
If your bag exceeds the depth limit, it will likely be gate-checked. Airlines measure all three dimensions, and a bag that is 22 by 14 by 10 inches does not meet the standard, even if the first two measurements are correct. Measure before you pack to avoid this problem.
Are carry-on size limits the same for all flights on the same airline?
Yes. Most airlines use the same carry-on limit for all domestic flights and all international flights, regardless of the aircraft type or route. However, some airlines have different rules for premium cabins or frequent-flyer members, so check your specific ticket or airline website to be sure.
Can I bring a carry-on bag and a checked bag on the same flight?
Yes. Your carry-on bag and personal item are separate from your checked luggage allowance. Most airlines allow one free checked bag on domestic flights, though budget airlines may charge for checked bags. Verify your airline's baggage policy before you travel.