The maximum number of linear inches on a checked bag for most airlines is 62 inches. This means that when you add up the length, width and height of the luggage you intend to check, it should not be more than 62 inches.Most standard suitcases, garment bags and duffel bags measure 62 linear inches or less.his means that when you add up the length, width and height of the luggage you intend to check, it should not be more than 62 inches. Most standard suitcases, garment bags and duffel bags measure 62 linear inches or less.