Measure your bag correctly

Once you know what you can take, ensure that you have a bag that meets those limits. Be sure to measure the entire length and width of your bag, including all handles and wheels (these can add more than an inch in some cases). Although you can always buy a new bag, the point of going carry-on is that you are not spending all that extra money. Luckily, most domestic carriers have very generous limits of over 50 linear inches. As a rule of thumb, you can almost always take a 19-, 20-, or 21-inch rolling bag onto a plane; most 22-inch bags will also fit. Above that, you might be asked to check your bag.