Calculate the shipping cost using a table of weight ranges and US Postal Service zip code zones.
USPS Zones are based on distance from the originating zip code. This plugin will use the merchant’s zip code as the origin and look up the USPS zone for the customer’s zip code and match up the weight of the customer’s order to the zone.
(Only the zip codes and zones are used from USPS; you can use whatever rates you want and don’t even have to ship with USPS.)
Go to the USPS Zone Chart lookup page and then copy and paste your zone chart into the plugin.