To find your 9-digit zip code, you can use the ZIP Code™ Lookup tool on the USPS website. You will need to enter your corporate or residential street address, city, and state to see a specific ZIP Code™. Alternatively, you can use the ZIP+4 Code Lookup tool on the SmartyStreets website. You can enter your 5-digit zip code to get a list of all the ZIP+4 Codes within that zip code. The last 4 digits of these 9-digit ZIP Codes usually represent 6-20 delivery points on a USPS carrier route. If you need more information, you can also try using the Full ZIP Code Lookup tool on the Postcodebase website.