Most airlines measure check-in luggage in linear dimensions, which means the sum of the length, width and height. The most common linear limit for check-in luggage is 62 inches, though it's prudent to confirm.
How do they measure carry-on luggage?
1. H x W x D: Most airlines use this formula to calculate bag size. For example, they might require dimensions like 22 x 14 x 9 inches, which is the most common set of dimensions for carry-ons.