Free tool
DIM weight calculator
Carriers charge for whichever is greater: the scale weight or the dimensional weight - the box's size divided by a divisor. Enter a packed box's dimensions and weight to see what it bills as, and what your 3PL should be rating it at.
- 139 - FedEx, UPS Daily, USPS (since July 2026)
- 166 - UPS Retail
- The divisor in my contract
- Cubic size
- 2,520 in³
- Dimensional weight
- 19 lb
- You are billed for
- 19 lb
Size wins: this box bills at 19 lb although it weighs 4 lb. If the dimensions on file at your 3PL are larger than the box that actually ships, every order pays the difference - check them.
This box is over one cubic foot (1,728 in³), so dimensional weight applies on USPS Priority Mail, Ground Advantage and Parcel Select too.
The result rounds the dimensional weight up as the carriers do: to the next whole pound, or to the next half kilogram, the step most express carriers bill metric weights in. Your contract's divisor decides your bill - if it promises 166 and your invoices rate at 139, the difference is disputable. How DIM weight reaches a 3PL invoice, and how to check it line by line, is in DIM weight explained. Feeproof recomputes every shipping line in a full audit; the first audit is free.