DIM Weight: Dimensional Weight
A billing weight based on a shipment's size rather than its actual scale weight, for low-density freight.
Dimensional (DIM) weight approximates how much space a shipment occupies relative to its actual weight, so carriers can price light, bulky freight fairly. Carriers calculate both the actual scale weight and the dimensional weight, then bill whichever is higher. DIM weight is standard in parcel and increasingly applied in LTL through the density-based freight class system.
Who publishes it
Set per-carrier; parcel carriers (UPS, FedEx) publish their DIM divisor annually. LTL uses the NMFC density framework instead of a single DIM divisor.
How to read it
- Parcel formula: (L × W × H in inches) ÷ DIM divisor = dimensional weight in pounds. Common divisors are 139 or 166 depending on carrier and service.
- The carrier bills the greater of actual weight or dimensional weight.
- LTL doesn't use a DIM divisor directly — density feeds into freight class instead, which achieves the same goal (pricing bulky, light freight higher).
Why it matters
DIM weight closes the loophole where light, oversized packages would otherwise ship cheaply while taking up a disproportionate amount of truck or van space. Shippers of bulky, low-density goods (e.g., packaging, insulation, apparel) often see DIM weight — not actual weight — drive their per-shipment cost.
Frequently asked questions
How do I calculate dimensional weight?
Multiply length × width × height in inches, then divide by the carrier's DIM divisor (commonly 139 or 166 for parcel). If that figure is higher than the actual scale weight, the carrier bills the dimensional weight instead.
Does dimensional weight apply to LTL freight?
Not directly as a DIM divisor — LTL uses the density-based NMFC freight class system instead, which achieves a similar result by classifying low-density (bulky, light) freight into higher, more expensive classes.
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