Dimensional Weight Calculator
Calculate the dimensional (volumetric) weight of a shipping package for UPS, FedEx, or USPS.
Enter length, width, and height to find the billable weight.
Dimensional weight (also called DIM weight or volumetric weight) is a pricing method couriers use to account for large, lightweight packages that take up disproportionate space in their trucks and aircraft.
Formula (in inches): DIM weight (lbs) = (Length × Width × Height) / DIM divisor
The DIM divisor varies by carrier:
- UPS domestic: 139
- FedEx domestic: 139
- USPS Priority Mail: 166 (for packages over 1 cubic foot)
- DHL Express: 139
Billable weight = whichever is greater: actual weight vs DIM weight
A box measuring 20 × 15 × 10 inches has a volume of 3,000 cubic inches. DIM weight at 139 = 3,000 / 139 = 21.6 lbs. If the box contains lightweight clothing weighing only 5 lbs, the carrier bills based on 21.6 lbs.
This is why ecommerce sellers sweat packaging dimensions. Reducing box size is often more impactful than reducing package weight. Cutting one inch off each dimension of a 20×15×10 box (to 19×14×9) reduces DIM weight from 21.6 to 17.2 lbs — a 20% reduction in shipping cost.
For international shipments using centimeters and kilograms, the DIM divisor is typically 5,000 (cm) for volume in cubic cm to kg. The calculator handles both imperial and metric inputs.
USPS applies DIM pricing only to Priority Mail packages that exceed 1 cubic foot (1,728 cubic inches). Below that threshold, you pay actual weight only.