DIM Weight 139 vs 166
For the same dimensions in inches, divisor 139 always produces a higher dimensional weight than 166. The smaller number divides package volume into more billable pounds.
Side-by-side calculation
Consider an 18 × 14 × 10 inch carton with a volume of 2,520 cubic inches.
| Divisor | Calculation | Raw DIM weight |
|---|---|---|
| 139 | 2,520 ÷ 139 | 18.13 lb |
| 166 | 2,520 ÷ 166 | 15.18 lb |
The 139 result is about 19% higher in this example. Carrier rounding can widen the practical difference.
What does DIM factor 139 mean?
It means 139 cubic inches are treated as one pound for the raw calculation. Factor 166 treats 166 cubic inches as one pound, allowing more volume per calculated pound.
Which factor should you use?
Use the factor tied to the selected carrier, service, rate type, origin, destination, and agreement. For example, UPS U.S. guidance distinguishes Daily Rates at 139 from Retail Rates at 166, while FedEx U.S. publishes 139 and current USPS guidance uses 166 in specified situations.
Read the UPS divisor guide, FedEx DIM guide, and USPS DIM guide for source-specific context.
Frequently asked questions
Is 139 or 166 better for the shipper?
For the same carton, 166 produces a lower dimensional weight, but you cannot choose freely; use the applicable carrier divisor.
How much higher is factor 139?
For identical volume, the raw 139 result is about 19.4% higher than the 166 result.
Does every carrier use the same factor?
No. Factors vary by carrier, service, market, rate type, and customer agreement.