Overview

Amazon sellers who use USPS as a shipping carrier through Buy Shipping need to understand the specific service restrictions, size-based surcharges, and compliance requirements that apply to their shipments. From nonstandard size fees that can stack up to $30 per package to dimension noncompliance penalties and special rules for military addresses, these policies directly affect shipping costs and account health. This reference guide breaks down the key USPS shipping rules every Amazon seller should have on their radar.

Key Points / What Sellers Need to Know

• USPS can refuse late packages — The USPS reserves the right to reject packages submitted after the original ship date printed on the shipping label, so sellers must ship promptly after purchasing labels.
• Transit times are dynamically adjusted — Amazon adjusts USPS transit times for certain origin-destination pairs based on historical delivery performance, which may cause some shipping products to become unavailable for specific orders.
• Nonstandard size fees can stack — Packages that exceed both length and cubic volume thresholds can be assessed two separate surcharges, potentially adding up to $30 in extra fees per package.
• Dimension noncompliance triggers a $1.50 penalty — If package dimensions in the electronic manifest are missing or inaccurate for parcels over one cubic foot or longer than 22 inches, USPS charges a $1.50 noncompliance fee.
• APO/FPO deliveries follow different rules — Standard USPS transit times do not apply to military addresses, and delivery confirmation only verifies that the military received the package, not the intended recipient.
• Flat Rate packaging has strict cubic inch limits — Products must physically fit within USPS-provided packaging, and each envelope size has a defined cubic inch maximum that cannot be exceeded.

Nonstandard Size Fees

Sellers shipping via USPS Ground Advantage, Priority Mail, Priority Mail Express, and related services should pay close attention to package dimensions. Packages between 22 and 30 inches long incur an Extended Parcel Handling (EPH) fee of $4.00. Packages exceeding 30 inches in length trigger a $7.00 surcharge. Additionally, any package with a volume greater than 2 cubic feet (3,456 cubic inches) faces a $15.00 fee. These fees can be assessed simultaneously — for example, a package that is 31 inches long and exceeds 2 cubic feet in volume would be charged both the $15.00 length fee and the $15.00 cubic volume fee, totaling $30.00 in surcharges on a single shipment. The maximum combined girth and length for any USPS package is 130 inches.