Will my bag fit as carry-on

Because the label measures the body and the airport measures everything. Wheels add two to four centimeters and a retracted handle adds one or two, which is why a “55 cm” case is usually 58–60 at the sizer. Measure the bag as it stands, from the floor to the top of the handle housing, and the answer stops being a surprise at the gate.

No, and that is deliberate. A case can be turned any way in the sizer, so the tool sorts your sides and the airline’s and compares longest to longest. Tools that compare width against width and height against height reject bags that would go straight in, which is the single most common mistake in this kind of check.

On most European and Asian airlines, yes, and it is checked at the gate with a hand scale. American carriers mostly do not publish a cabin weight limit at all, which is why those rows show size only. Where a limit exists the tool applies it, because a bag that fits the frame and exceeds the weight is stopped just the same.

Because on their basic fare the free allowance is the personal item alone — the cabin bag in the table is a paid extra. The dimensions are honest, but a passenger reading only them would arrive expecting to bring the bag for free. That is the most expensive place to be wrong, so it gets said in words.

Above the list is the date on which every limit was checked against what the airlines themselves publish. Carriers change them, sometimes without notice, so before flying it is worth re-checking on the airline site — each row links to the official page. If you spot a discrepancy, tell us: there is a form at the bottom.