Though some airlines give you a few extra inches here and there, the major domestic carriers are all in agreement: the maximum allowable carry-on bag is 22″ x 14″ x 9″. This standard has been in place for years, but in the past airlines were lenient about ensuring bags adhered to it. Today, however, most airlines have been enforcing their size limits. So to play it safe, invest in a suitcase or duffel bag that doesn’t exceed those measurements.
Once you’ve identified a few bags that meet your size requirements, compare the interior packing space. Get a carry-on that has as much interior capacity as possible. Don’t judge the capacity—measured in cubic inches/centimeters or in liters—based on exterior dimensions: Two bags with the same external dimensions can have wildly different internal capacity.
A lightweight, wheeled carry-on-size bag will be 7.5 pounds or less, experts say. Weight becomes particularly important on flights outside the United States, where carry-on weight is usually taken into account. Some U.S. airlines as well are beginning to impose weight restrictions on carry-on. You want to avoid heavy bags that, when empty, use up too much of the total allowable weight.
What size carry-on do I get for foreign airlines?
If you are traveling on a foreign airline on a flight that begins or ends in the United States, the rules of the U.S. partner airline apply.
However, for flights that begin and end outside of the United States, all bets are off. The U.S. lowest common denominator of 22 inches high x 9 inches deep x 14 inches wide is rarely the right shape or size for out-of-country travel. In general—and it’s always wise to check before you fly—foreign flights without a stop in the United States require a shorter bag, usually 21 inches, but it can often be wider, and it is typical for weight restrictions to apply.
So what size carry-on should you get?
It’s easy if you only travel on one airline: Check the allowable carry-on size and buy one that fits. If you don’t play favorites with airlines, you have to decide if you want to buy the smallest bag that will get you onto any plane, or if you want to buy two or more to take advantage of the opportunity to use a larger carry-on on airlines that permit it.
How do you know the carry-on’s dimensions?
This is a trickier question than you would think. First rule of thumb: Ignore hang tags, advertisements, and website product descriptions that proclaim something like “Official Carry-On Size.” Even crazier: Ignore the stated measurements listed. Frequently, the measurements are inaccurate. When buying online, ask the seller if the given size reflects the external dimensions including wheels and handles. When buying at a brick-and-mortar retailer, bring a tape measure to check for yourself. Remember: with the bag standing vertically, measure from the floor to the top of the handle (retracted) for height; front to back at its widest point for the depth; and left to right at the widest point for the width.