If you are shipping Priority Mail or Priority Mail Express* you have the option of using Flat Rate boxes and envelopes, or Non-Flat Rate Priority boxes provided free of charge from USPS.

Note: If using Priority Mail Express, the only flat rate packaging options available are: Flat Rate Envelope, Legal Flat Rate Envelope or Padded Flat Rate Envelope. If you use a Flat Rate box in combination with a label you have selected Priority Mail Express, USPS downgrades the service to Priority.

With all priority packaging, contents must fit comfortably and packing must be sealed without any bulging.

Shipping Distances

USPS uses the term "zones" to describe the distance a domestic shipment must travel. Zones range from Zone 1 (local) to Zone 9 (very far away). A zone is determined by the "ship from" zip code as it relates to the "ship to" zip code. The farther a package must travel, the more zones it crosses, and the more it costs to ship it. The first 3 digits of your destination ZIP Code determine the zone. To look up the zone for your shipment visit: USPS Zone Lookup.

Non-Flat Rate boxes are also available when sending Priority or Priority Mail Express service. In general weight-based rates are sometimes better for shipments traveling shorter distances while Flat Rate packages have an advantage for heavier parcels traveling further.

To see all package options and order free supplies visit: USPS Store.

Note: External links are maintained by third parties and are provided here as a convenience only. Descartes does not endorse, approve or make any claims as to the accuracy or reliability of the contents, which may be changed from time to time by the third party without warning.

Below are the most commonly used sizes for Flat Rate boxes and envelopes and Non-Flat Rate Priority boxes.

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