USPS Aligns Dimensional Pricing with FedEx and UPS, Raising New Cost Concerns for Ecommerce Sellers

The United States Postal Service (USPS) plans to change how it calculates dimensional pricing for large, lightweight packages beginning July 12, bringing its pricing model closer to FedEx and UPS.

Under the changes, USPS will round up fractional package measurements to the next whole inch. For example, a package measuring 12.2 inches will be billed as 13 inches. USPS also plans to lower its dimensional weight divisor from 166 to 139 for several shipping services, including Priority Mail, USPS Ground Advantage, and Parcel Select.

For ecommerce sellers, the changes may increase shipping costs for bulky but lightweight products because more shipments could be billed based on package size rather than actual weight. Sellers that rely heavily on USPS for low-margin or oversized shipments may see additional pressure on fulfillment costs and profitability.

The update reflects a broader industry trend as carriers focus more heavily on the amount of space packages occupy within delivery networks. FedEx and UPS introduced similar dimensional rounding practices last year.

Ecommerce sellers can prepare by reviewing packaging configurations, reducing excess box space, and comparing carrier rates across services. Businesses may also benefit from multi-carrier shipping software that automates rate shopping and helps optimize fulfillment decisions as pricing structures evolve.

Book a Descartes demo to learn how our ecommerce shipping solutions can help you reduce shipping costs, optimize packaging strategies, and adapt to changing carrier pricing rules.