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Dimensional weight calculator: DIM divisor 139 vs 166
Compare how DIM divisors such as 139 and 166 affect the billable weight of a package.
Source: Standard published dimensional divisors · Divisors as published by the carriers; prices from FedEx Standard List Rates, effective January 5, 2026 · Free, no signup
| Divisor | Dimensional weight | Billable weight | What governs | Published rate, zone 5 |
|---|---|---|---|---|
| 139 | 22 lb | 22 lb | dim | $28.28 |
| 166 | 19 lb | 19 lb | dim | $26.42 |
| 194 | 16 lb | 16 lb | dim | $23.41 |
| 250 | 13 lb | 13 lb | dim | $21.69 |
This box is billed at 22 lb under divisor 139, so dimensional weight applies until the package actually weighs more than 22 lb. Below that, you are paying for empty space. The divisor is a negotiated term. Moving from 139 to 166 is a real request to make, and it applies to every package large enough to be dimensioned, not just one lane or service. Rates shown are FedEx published Ground list rates before any discount, fuel or accessorials.
See how your agreement changes this result.
This calculator shows the effect on one package. We can use your shipment data to estimate the total cost of dimensional weight and assess whether a different divisor is worth negotiating.
What is dim divisor?
A dimensional divisor turns package volume into a billable weight: length times width times height, divided by the divisor. Carriers bill the greater of actual and dimensional weight. A lower divisor gives a higher billable weight, so moving from 166 to 139 raises the calculated weight of every dimensioned package by about 19% before rounding, with no change to the rate card.
Worked example
An 18 by 14 by 12 inch box is 3,024 cubic inches. Divided by 139 that is 22 lb, and by 166 it is 19 lb, so a 6 lb packed carton is billed as 22 lb or 19 lb. At zone 5 list rates that is $28.28 against $26.42, where the actual 6 lb would list at $18.60. Packed in a 16 by 12 by 10 inch box instead, it bills at 14 lb and $22.23 on the standard 139.
Published rates, not your agreement
The calculator applies the standard formula and prices the result at FedEx Ground list rates before any incentive. It does not apply your incentive, the minimum billable weights for additional handling and oversize packages, or USPS rules for packages under one cubic foot. It shows one package; the annual cost depends on how many of your packages are dimensioned.
Source: Standard published dimensional divisors. Divisors as published by the carriers; prices from FedEx Standard List Rates, effective January 5, 2026.
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