Effective July 12, 2026, the U.S. Postal Service will implement updates to how dimensional (DIM) weight is calculated for competitive shipping services. These updates are designed to better reflect the costs of transporting large, lightweight parcels and to align our pricing structure with current industry standards.
Impacted Services:
Priority Mail Express
Priority Mail
USPS Ground Advantage
Parcel Select
Dimensional weight pricing applies to packages that exceed 1,728 cubic inches (one cubic foot). For these items, two specific changes will take effect:
— New DIM Divisor: The divisor used to calculate dimensional weight will change from 166 to 139.
— Result: This change ensures that the price of a package more accurately represents the space it occupies in our transport network.
— Updated Rounding Rules: We are moving to a consistent “Round Up” rule for all package dimensions. — New Rule: Any fraction of an inch must be rounded up to the next whole inch. For example, a measurement of 12.2 inches will be calculated as 13 inches.
These adjustments allow USPS to continue providing reliable, nationwide service while managing the capacity of our ground and air networks efficiently.
By aligning calculation methods with those used across the shipping industry, the USPS will provide a more consistent experience for businesses and consumers alike.
Please direct any inquiries to ShippingServices@usps.gov