What's the right size for carry-on luggage?

In the 2009 film "Up in the Air," George Clooney's character Ryan Bingham extols the virtue of the carry-on, telling Anna Kendrick's Natalie Keener that an airline traveler loses a ton of time by checking a piece of luggage and having to get it from baggage claim: "35 minutes a flight. I travel 270 days a year. That's 157 hours. That makes seven days. You're willing to throw away an entire week on that?"

Even if you travel a small fraction of the amount that Clooney's frequent-flying corporate hatchet man did, carry-on luggage might still have big appeal to you. Most U.S. airlines don't charge a fee for one carry-on bag, though most do hit you up to check a bag.

Where it gets tricky is selecting a carry-on that meets an airline's size restrictions. Use these tips to find carry-on luggage that will measure up.

For more information, check our luggage buying guide. Also, find out why buying a new carry-on bag can save you money.

Sizing it up

When airlines refer to “carry-on luggage” or “carry-on baggage,” they mean the bag that meets size specifications to store it in the overhead bin.

Trouble is, there is no such thing as a standard carry-on size. Every U.S. airline has its own rules. The big three—American, Delta, and United/U.S. Airways—have settled on a uniform size (for now). It’s 22 inches high x 9 inches deep x 14 inches wide—these are external dimensions, including wheels and the handle. A few U.S. airlines are more generous with their carry-on size allowance, but some also impose weight restrictions and/or fees for carry-on baggage.

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.

What size 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 bag’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.

Capacity

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.

How do you measure the packing capacity? Outside of creating a lab project for an applied physics class, you can’t. So you have to inspect the bag for certain tell-tale signs, such as:

  • Squared edges. Interior volume is sacrificed with curved corners.

  • No protrusions. An exterior, protruding pouch reduces total packing space. Compartments accessible from outside the bag should be configured as inline pockets, not pouches that appear as protrusions.

  • No wheels. If you really need every possible inch of interior space, forgo wheels. While the wheels contribute to the overall dimensions of the bag, they displace potential packing area.

  • Externally mounted handle. This would be a best-case scenario. Most handles are mounted internally. But if you absolutely must be able to harness every square inch of packing space, external is the way to go.

Weight

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.

Susan Feinstein



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