UPS DIM weight or dimensional weight is how UPS calculates shipping charges based on package size, not just actual weight.
If a box is large but lightweight (like pillows or plastic containers), UPS may charge based on its dimensional weight instead of its scale weight.
How UPS calculates dimensional weight?
Formula (U.S. domestic shipments):
Dimensional Weight (lbs)
=
Length × Width × Height (in inches)
139
- Divide cubic inches by 139 (UPS dimensional divisor).
- You must round every fractional inch up to the next whole inch before calculating.
- UPS charges whichever is greater:
- Actual weight
- Dimensional weight
Example
Box size: 20″ × 20″ × 20″
Actual weight: 10 lbs
- Volume = 20 × 20 × 20 = 8,000 cubic inches
- 8,000 ÷ 139 = 57.55
- Rounded up = 58 lbs dim weight
Even though it weighs 10 lbs, UPS would charge for 58 lbs.
Why UPS uses DIM weight?
Carriers like UPS use dimensional weight because:
- Large packages take up more truck/plane space
- Space is limited and valuable
- It ensures fair pricing for bulky shipments
Does this apply everywhere?
- Applies to most domestic and international shipments
- The divisor (139) may differ for certain contracts or international lanes