USPS Moves to Align Dimensional Weight Pricing with FedEx and UPS — Changes Take Effect July 12
- May 23
- 1 min read
Effective July 12, 2026, the U.S. Postal Service will implement two significant changes to how it calculates dimensional weight pricing — bringing its methodology in line with FedEx and UPS. These updates will increase shipping costs for lightweight, oversized packages across several USPS services.
What's Changing
1. Rounding Up Fractional Measurements
USPS will round all fractional package dimensions up to the next whole inch. For example, a package measuring 12.2 inches will now be calculated as 13 inches. UPS and FedEx adopted this same practice in 2025.
2. New Dimensional Weight Divisor: 139 (down from 166)
Dimensional weight is calculated by multiplying L × W × H, then dividing by a divisor. USPS is lowering its divisor from 166 to 139 — the same figure used by FedEx and UPS for daily rates. A lower divisor means a higher dimensional weight result, triggering dim-weight billing on more packages.
Services Affected
Applies to packages exceeding 1 cubic foot:
• Ground Advantage
• Parcel Select
• Priority Mail
• Priority Mail Express
What This Means
• Lightweight but bulky packages will see cost increases as more shipments qualify for dim-weight billing.
• The combined effect of rounding up + lower divisor amplifies exposure for shippers with irregular package profiles.
• July 12 is also the date USPS expands its dimensional reporting requirements and eliminates ounce-based rate differences for Ground Advantage Commercial shipments.