Dimensional Weight (DIM Weight)

Dimensional weight – DIM weight – is a pricing method that charges based on the space a package occupies rather than just how much it weighs. Carriers calculate DIM weight by multiplying the package's length, width, and height, then dividing by a DIM factor (a carrier-specific divisor, typically 139 for domestic parcel or 166 for international). The shipper is billed on whichever is greater: the actual weight or the DIM weight. This prevents carriers from filling a truck with light, bulky packages that take up space but generate minimal revenue based on actual weight alone.

DIM weight pricing is standard in parcel shipping (UPS, FedEx) and increasingly applied in LTL and air freight. For parcel-heavy shippers – particularly in e-commerce, CPG, and food – DIM weight can be a significant cost driver, especially when products are shipped in oversized boxes with excessive void fill. A 2-pound item in a large box may be billed at 8 or 10 pounds of DIM weight, quadrupling the shipping cost relative to actual weight.

Managing DIM weight requires two things: right-sizing packaging to minimize empty space, and maintaining accurate package dimensions in your shipping systems so rate quotes reflect what you'll actually be billed. Shippers who estimate dimensions or use generic box sizes in their systems often face invoice charges higher than their quoted rates – because the quote was based on inaccurate dimensions and the carrier measured the actual package. This is a common source of billing discrepancies in parcel and LTL, and it compounds at high volumes.