Navigate your Web browser to one of several geocoding websites. You may also enter "free geocoding" into your search field to find others.
Choose a service you are interested in after looking at its Web page. A couple of examples include Geocoder and GPS Visualizer, but many others exist.
Get the physical address and zip code of the building in which your P.O. box is located. Enter one of these (or both, depending on the website) into the appropriate field(s) on the site.
Wait for the results. The geocoding service should give you both the latitude and longitude of the address information you entered.
Continue waiting if the website you selected provides mapping of your geocode. A mapped result should appear after a few minutes if the website offers this service.
