|Original Address||Street Address|
|John Doe||John Doe|
|PO Box 20015||39 W 31ST ST UNIT 20015|
|New York, NY 10001||New York, NY 10001|
We've created a spreadsheet for looking up the correct competitive street address for a given PO box address. Essentially, you look up the zip code in the list and use the corresponding address, adding "Unit" plus the PO box number.
Sometimes there is more than one post office for a given zip code, so you'd also match the PO box against the list of box number ranges for each address.
It might sound a little more complicated than it is, but the spreadsheet includes instructions with pictures which should make it clear.
The spreadsheet is on Google docs (no login needed):
Smart Post PO Box Address Lookup
Note that some zip codes are absent from the spreadsheet (and from the USPS source for this information). At this time, we are not sure why some zip codes are missing. However, as an alternate method, you can look up the post office for a particular zip code using the find locations tool on USPS.com
If more than one post office is listed with the same zip code, you may need to call to find out if the post office box is located there.
It may help to limit the search to post offices and not approved postal providers, but for some zip codes there is only an approved postal provider that actually houses the PO boxes (e.g. zip codes for universities which have their own mail handling facilities).