Almost all U.S. LTL carriers use NMFC freight classes, although some are attempting to move to a dimensionally-based system.

No. If you claim that your freight is a lower class than it actually is, your carrier will likely find out. They will charge you a fee for reclassifying the freight and charge you the appropriate amount for the actual class of your freight after it has been shipped.

NMFC freight classes are determined using four factors: density, handling, stowability, and liability. All of these factors affect the cost to the carrier of shipping goods.