Dimensional Weight Calculator
Carriers bill the greater of actual weight and dimensional (DIM) weight. Compute DIM weight from your dimensions and the carrier's DIM divisor.
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Result
Enter dimensions and weight
How is dimensional weight calculated?
Dimensional weight (also called DIM weight or volumetric weight) converts a package's volume into a billable weight using the carrier's divisor:
Dimensions are in inches and the result is in pounds. You are billed on the greater of actual weight and DIM weight, so a light-but-bulky package is charged on its size, not its scale weight. A lower divisor (139) produces a higher DIM weight than a higher divisor (166), so the divisor your carrier uses directly changes the bill.
Worked example
A box measuring 24 × 18 × 12 in that weighs 15 lbs on the scale, shipped at a divisor of 139:
Even though the box weighs 15 lbs, you pay for 37.3 lbs because it takes up more space than its weight implies. Switch the divisor to 166 and the DIM weight drops to 31.2 lbs - same box, different bill.
Why do carriers use dimensional weight?
Trucks and planes run out of space long before they run out of weight capacity. A trailer full of pillows weighs almost nothing but fills the cube. DIM weight lets carriers charge for the space a shipment consumes, not just its mass - which is why it matters most for low-density parcels (foam, apparel, plastics) and rarely changes the bill for dense freight like steel or machinery.
Common DIM divisors
| Divisor | Typically used for | Effect on bill |
|---|---|---|
| 139 | Common US domestic parcel | Highest DIM weight |
| 166 | International / lighter packages | Lower DIM weight |
| 194 | Some negotiated / legacy rates | Lower still |
| 250 | Freight / pallet-level divisors | Lowest DIM weight |
Always confirm the exact divisor in your carrier contract - it varies by carrier, service level, and whether the shipment is domestic or international. For LTL freight, pricing is driven by density-based freight class rather than a divisor; use the Freight Class Calculator for that.
Dimensional weight FAQ
What is dimensional weight?
Dimensional (DIM) weight is a billable weight calculated from a package's volume - length × width × height ÷ a carrier divisor. Carriers bill the greater of DIM weight and actual scale weight so they can charge for the space a shipment occupies.
How do I calculate dimensional weight?
Multiply length × width × height in inches to get cubic inches, then divide by the carrier's DIM divisor (commonly 139 or 166). The result is the dimensional weight in pounds. You pay on whichever is greater: DIM weight or actual weight.
What DIM divisor should I use?
It depends on your carrier and service. 139 is common for US domestic parcels, 166 for international or lighter shipments. The lower the divisor, the higher the DIM weight and the more you pay. Always confirm the exact divisor in your rate agreement.
When does dimensional weight matter?
DIM weight matters whenever a package is large but light - its volume-based weight exceeds its scale weight. Dense shipments (steel, machinery) are usually billed on actual weight, so DIM weight rarely applies to them.