Dimensional Weight

Dimensional weight — also called volumetric weight — is how parcel carriers (USPS, UPS, FedEx) charge for packages that are large but light. The carrier compares a package’s actual weight to its dimensional weight and bills the greater of the two.

DIM weight is calculated by multiplying length × width × height in inches and dividing by a carrier’s DIM divisor (commonly 139 for domestic parcel). A big, lightweight box can therefore cost as if it weighed far more than the scale shows.

The concept is closely related to LTL freight density: both price freight by the space it consumes rather than weight alone. Reducing package size — or palletizing efficiently — is the main lever for lowering dimensional charges.