DIM weight calculator
See what UPS, FedEx and USPS will actually bill for a box, and the largest box that still bills at actual weight. Updated for the USPS divisor change to 139 on July 12, 2026.
| Carrier | Divisor | DIM weight | Billable | Max box at actual weight |
|---|---|---|---|---|
UPS (Daily Rates) Some retail and contract rates use 166. | 139 | 14 lb | 14 lb | 417 in³ |
FedEx Most domestic services. | 139 | 14 lb | 14 lb | 417 in³ |
USPS Only parcels over 1 cubic foot. | 139 | 14 lb | 14 lb | 1,728 in³ |
UPS (Retail / 166) Retail counter and some contracts. | 166 | 12 lb | 12 lb | 498 in³ |
Dimensions are rounded up to the next whole inch, and weight to the next pound, before calculating. Orange means you're paying for DIM weight. A box at or under the last column's volume would bill at actual weight.
How DIM weight works
Carriers charge for the larger of a package's actual weight and its dimensional weight. DIM weight is length × width × height in inches, divided by the carrier's divisor and rounded up to the next pound. Each dimension is rounded up to the next whole inch first.
A lower divisor means a higher DIM weight. Moving from 166 to 139 adds about 19% to the DIM weight of every box, so oversized packaging costs more than it used to.
Read more in the USPS 139 divisor guide, or run your whole SKU list through the bulk tool.