Whether you're hauling three checked bags or toting a single carry-on to your next flight, rest assured that the airlines are keeping closer watch than ever on the size of your luggage. The best way to avoid unexpected fees for oversize luggage – or the unpleasant surprise that your carry-on doesn't really fit into the airline's bag sizer – is taking a few minutes to measure your luggage at home.

Airlines Set the Sizing Regulations

Before you whip out the measuring tape, take a moment to check your airline's sizing requirements on their website. Each airline sets it own sizing regulations for baggage size, but that said, the checked baggage allowances are fairly standardized across the board at 62 linear inches. ("Linear inches" is the sum total of the bag's length, width and height.) Carry-on allowances tend to vary more widely, but a size limit of 22 by 14 by 9 inches is common. Airlines also allow you one small personal item in the aircraft cabin, and, again, the exact dimensions vary; as a general rule, if it will fit completely under the seat in front of you, it can go.

Don't Believe the Manufacturers

You'd think that luggage manufacturers would measure their products the same way that airlines do – but that isn't always the case. Manufacturers often don't include wheels and handles in their measurements, which can lead to a nasty surprise if you buy a carry-on, thinking it'll fit your airline's sizing regulations, only to find out that the overhead bin can't close because of its wheels or handle. Some manufacturers have also been known to give the interior measurements of their bags instead of the exterior measurements. So, don't be shy about taking your measuring tape when you go shopping for luggage, or at least checking the bag labels to see if what the measurements do and don't include.

Measuring Length, Width and Depth

Ready to measure your suitcase? Regardless of whether you're at home or in a store, grab your measuring tape and move around the bag as you check its dimensions. Measure the height from the top of the bag down to the ground, with the handle retracted (collapsed) as far as possible. Measure width from one side of the bag to the other; some bags are tapered for stability, so make sure you're measuring at the widest point. Then check the bag's depth from front to back. Again, take your measurement at the widest point, especially if it has exterior pockets on your bag or you've packed it to the point that it bulges.


Ready to pack your carry-on? Make sure you review the U.S. Transportation Security Administration's rules for packing liquids and general prohibited items.