WP e-Commerce USPS Shipping Extension



    • USPS requires you to be using US dollars
    • United States, Puerto Rico and the US Virgin Islands can be used as your base country (origin)
    • Dimension & Weight units set to Inches & lbs-oz


  • SimpleXML installed
  • The plugin needs to be able to talk to USPS API. For this it uses wp_remote_post which makes use of fsockopen/CURL.

Calculate shipping costs using the USPS API


USPS is the largest delivery network in United States, this plugin will provide you real-time shipping rates by utilizing their API. The rate returned is based on products dimensions and volume.

To ensure the accuracy when returning a rate from the USPS API it requires, the shipping country, state and Post code/Zip code.

The features of the extension are:

  • This plugin offers a number of shipping methods for both International Shipping and Domestic shipping.
  • You can choose specific shipping Services's to display at the checkout.
  • You can create Custom boxes to suit the size of your products.
  • Using your custom box, you can define the number of items you would like to pack into the custom box and also the maximum weight.
  • You can add a handling fee.
  • Set a fallback rate, if the USPS APi ever goes down, your customers will always be presented with a price.
  • You can re-name the shipping service title's to suit your Website.
  • The product dimensions and weight will be used to pack your items into your Custom Boxes or the pre-defined boxes, once a box has reached it's full capacity (using the dimensions and weight of your
    product), another box will be added. A Box Packing Algorithm.
  • You can set up as many Customised Boxes as you need to. There is no limit.
  • You can define on the Checkout page which shipping Services you would like to display: Cheapest Rate, Highest Rate or All.

All of our Extensions are developed and Supported by Extension Works, there are no 3rd party developers involved. This will ensure that your request's if any, are handled by Extensions Works in a timely and prompt manner. This we can guarantee.

This extension offers the following Shipping Services:


First Class mail
First-Class Large Postcards
First-Class Keys and IDs
First-Class Postcard Stamped
Priority Mail
Priority Mail Keys and IDs
Priority Mail Flat Rate Small Box
Priority Mail Flat Rate Medium Box
Priority Mail Flat Rate Large Box
Express Mail Hold for Pickup
Express Mail PO to Address
Express Mail Sunday/Holiday
Express Mail Flat Rate Boxes
Express Mail Flat Rate Boxes (Hold For Pickup)
Express Mail Padded Flat Rate Envelope
Standard Post
Bound Printed Matter
Media Mail
Library Mail


First Class Mail International Parcel
Priority Mail International
Priority Mail International Flat Rate Small Box
Priority Mail International Flat Rate Medium Box
Priority Mail International Flat Rate Large Box
Priority Mail International DVD Flat Rate Box
Priority Mail International Large Video Flat Rate Box
Express Mail International
Express Mail International Flat Rate Boxes
Global Express Guaranteed
Global Express Guaranteed Document used
Global Express Guaranteed Non-Document Rectangular
Global Express Guaranteed Non-Document Non-Rectangular

WP eCommerce USPS Shipping ExtensionWP eCommerce USPS Shipping Extension

Extensions tested on a Single Site Installation, multisite installations not recommended.

Wordpress:Requires at least: 3.1
Wordpress:Tested up to: 4.1.3
WP eCommerce:Stable tag: 3.9.1


The box packer is volume based. This will in most cases provide good results, but will never be as accurate as a real person packing a box (see BIN Packing Problem) therefore it is important you understand that packing results are as accurate as they can be and any anomalies should be accepted.)

Upgrading from an old version?

Upgrade from WP e-Commerce USPS Shipping Extension for just $29.00 by entering your details below.

SKU: wpec-usps. Category: . Tag: .

Product Description

Offer USPS shipping rates using our Premium WP e-Commerce USPS Shipping Extension and the USPS API.

Upon purchase of a product at Extension Works, you purchase a Single Website licence.

  • The Single Website Licence includes 1 year of Activation, Updates (Automatic Updates via your WordPress admin area) and Support.
  • After the 1 year period, your Single Website Licence will expire, you will need to purchase a Licence Key Upgrade to continue to use the product, you will have no download access for the product from your Extension Works Account and you will have no updates available via the WordPress admin area.
  • Before the term of 1 year expires, you will need to purchase an Upgrade for your Licence Key to receive the discounted priceAfter the term of 1 year you will need to purchase a new licence key at full price.
  • Extension Works will provide Licence Key Renewal email notifications, to let you know your licence key will expire soon.