Source order
This cluster uses carrier service guides, carrier support pages, USPS Postal Explorer, and Federal Register changes before third-party logistics commentary. Third-party pages were not used to set calculator rules when an official carrier source was available.
| Rule area | Implemented value | Official source | Limit |
|---|---|---|---|
| FedEx package DIM | Service Guide package DIM rule applied; divisor 139; effective_from is NOT_VERIFIED for the dimension-rounding change. | FedEx Service Guide 2026 and FedEx DIM explainer | International Deferred Freight divisor 166 and freight handling-unit rules are excluded. |
| UPS Daily package DIM | Fractional dimensions round up; divisor 139; compare actual and DIM. | UPS Daily Rate and Service Guide and UPS dimensions support | Simple Rate, freight, large-package minimums, and surcharges are excluded. |
| UPS Retail package rate type | Retail is kept as a separate rate type; calculator uses the public package DIM method and labels Retail separately. | UPS Retail Rates 2026 and UPS Terms | Retail dollar rates are not calculated. |
| USPS before 2026-07-12 | Nearest-inch dimensions; divisor 166; DIM only if volume exceeds 1,728 cubic inches. | USPS DMM 123 | Postal product price tables and ounce-tier postage are not calculated. |
| USPS from 2026-07-12 | Dimensions round up; divisor 139; DIM only if volume exceeds 1,728 cubic inches. | Federal Register change | Hazmat, noncompliance, length, cubic, and oversized fees are excluded. |
What is deliberately excluded
The calculator does not estimate final shipping charges. It excludes fuel surcharges, negotiated account rates, retail counter differences beyond the selected rate type, additional handling, large-package surcharge, minimum billable weights for large packages, hazardous-material fees, dimensional noncompliance fees, delivery area fees, residential fees, taxes, duties, declared value, pickup fees, returns rules, flat-rate packaging prices, and carrier audit adjustments.
Rounding policy used in the calculator
FedEx source priority: when the general FedEx DIM explainer and the contract-oriented FedEx Service Guide differ, this calculator applies the Service Guide rule because it is the controlling rate, terms, and conditions document for this source set. The FedEx general DIM explainer says to round each measurement to the nearest whole inch, while the 2026 Service Guide source set reviewed for this tool supports using the package DIM method with a 139 divisor and contract-document priority. Because no direct official DIM-rule effective date for the FedEx dimension-rounding change was found, FedEx effective_from is shown as NOT_VERIFIED.
UPS package and USPS from 2026-07-12 rules use upward rounding for fractional dimensions. USPS before 2026-07-12 uses the DMM wording to round off measurements to the nearest whole inch, then applies the 1,728 cubic inch threshold and 166 divisor. DIM weight is rounded up to the next whole pound when it applies.
Verification notes
Official source pages and PDFs were checked again on 2026-07-10. If a carrier account, marketplace label system, or retail location shows a different rule, use that carrier-controlled quote flow as the final authority for that shipment. Report source changes through the Corrections Policy.