Freight Class Calculator

Shipping cost is really about how much trailer space a shipment occupies relative to what it weighs, not weight alone. A pallet of bricks and a pallet of pillows can weigh very differently for the same footprint, and the carrier's truck has both a weight limit and a space limit. Density (pounds per cubic foot) captures that space-versus-weight tradeoff in one number, which is why the NMFC classification system is built around density bands rather than a simple weight threshold.

This calculator flags a shipment as oversize when any single dimension exceeds 96 inches (8 feet), separately from the density-based freight class calculation. Oversize freight often triggers additional handling fees or special routing from carriers regardless of its density class, since it may not fit standard dock equipment or trailer configurations, so it is worth checking both the freight class and the oversize flag before requesting a quote.

Yes, and this is one of the more common points of confusion in LTL shipping. Two 50-pound shipments can land in very different classes if one is packed into a small, dense box and the other is packed loosely into a much larger box -- the larger box has lower density (fewer pounds per cubic foot) and therefore a higher, more expensive freight class, even though the weight on the bill of lading is identical.

Carriers physically weigh and measure freight at their terminals, and if the actual density differs from what was declared when the shipment was booked, they will rebill at the correct class -- typically a higher, more expensive one if the shipment was denser or bulkier than reported. Using accurate weight and dimensions up front, and remembering that density is only one of the NMFC's four classification factors, reduces the chance of a reclassification charge arriving after the fact.