Carry-on bags are limited to 22 inches long, 14 inches wide and 9 inches high including wheels and handles. All three measurements shouldn't add up to more than 45 inches.

To determine if your carry-on bag is allowed, you must check the specific dimensions and weight limits of the airline you are flying, as these are not universal. In 2026, many airlines have moved to a standardized sizing of 55cm x 40cm x 20cm (approx. 22" x 16" x 8"), but budget carriers often have smaller limits. The easiest way to check is to look at your booking confirmation or the "Baggage" section of the airline's mobile app. Most major airports also provide "sizing crates" at the check-in counters where you can physically test if your bag fits. Beyond size, pay attention to weight; while many U.S. domestic airlines don't weigh carry-ons, international and low-cost carriers often enforce a 7kg to 10kg limit. If your bag is overweight or over-sized, you may be forced to check it at the gate for a significantly higher fee than if you had paid in advance. Finally, ensure your bag contains no prohibited items like liquids over 100ml (unless using a CT-scanner equipped terminal) or loose lithium batteries, which must always be in carry-on.