The four cardinal questions for understanding airline luggage rules are: How big? How many? How heavy? How much? Airlines restrict the size, weight, and number of bags you can carry on and/or check. Exceed any of the limits, and you’ll find out how much the overage will cost you.
Before you pick your luggage, know the rules. Unfortunately, there’s no law or universal standard governing the size, weight, or number of suitcases you can carry on or check. Each airline sets and enforces its own rules. Your best bet is to check your carrier’s website each and every time you travel.
In selecting new luggage that will conform to the rules of most airlines, here a few general guidelines.
Carry-on: In the United States, most domestic flights allow carry-on bags that measure no more than 45 linear inches (upright height + depth + width). The most common configuration is 22” x 9” x 14”. But some carriers, such as regional commuter jets and international airlines, impose smaller carry-on limits. When shopping, don’t accept the bag’s advertised measurements at face value. Measure the dimensions yourself and make sure your measuring accounts for all parts that jut out from the main body, such as pouches, wheels, and unretractable handles.
Checked baggage: With a few notable exceptions, most airlines charge for any number, size, or weight. But you’ll incur an even bigger fee if your bag exceeds the rule-of-thumb 62 linear inches (again, including protrusions) for domestic flights. Outside the U.S., the cumulative weight, rather than the size, is often the most important factor.
Carry-on: Although U.S. domestic airlines are not currently imposing a weight limit, don’t assume you can carry on 100 pounds of bricks inside your 22” x 9’ x 14” bag. If you can’t lift it yourself into the overhead bin, you’ll probably be asked to check it. International carriers might have weight restrictions. As always, check before you pack.
Checked baggage: In the U.S., 50 pounds is the usual limit. An overweight bag will add a fee to your tab. Outside the U.S., restrictions on total cumulative weight of your checked luggage might apply. Some foreign carriers even have minimum size and weight rules. Check.
To, from, and within the United States, the answer is usually (but not always) this: one checked bag (stored in the plane's luggage hold), one carry-on bag (stored in the cabin’s overhead bin), and one personal item (stowed beneath the seat in front of you). Flights completely outside the U.S. might be more concerned about weight of your checked baggage than the number of pieces.
How much (does it cost)?
Domestically, a checked bag can run you $25 to $100 dollars—and up to $200 additional if the bag is overweight or oversize. Jet Blue does not charge for the first piece of checked luggage, and Southwest has no fee for two pieces. (Polices change frequently, so always check before you go.) Other airlines offer free baggage check for certain passengers, such as those flying first- or business-class, or those who are members in special airline programs.