ZIP Code Questions

Basic Questions

Q: Why is your data more expensive than some competitors?

A: We were the first company to offer this data over the Internet (back in 1994) and had to create it from scratch. We've since have had many competitors use our data in their products without our permission and then sell it for a fraction of the price (since they didn't have to put in thousands of hours to develop a product). We continually update our data in order to stay ahead of the competition.

Q: Do you re-sell USPS data like your competitors?

A: The U.S. Postal Service creates their data for their own internal use, and re-sells it to others who want to use it. It is sold 'as is' and has a lot of errors and limitations we don't like, so we build our own data, which is more labor-intensive, but the results are much better.

For instance, in the USPS data there are many locations where the city or county are just plain wrong. An example of this is when Dade county changed their name to Miami-Dade. We changed our product immediately and it took about two years for the USPS data to be changed. Some of the cities assigned to ZIP Codes are not valid city names, so we override them.

Another important difference is that the USPS does not use periods, hyphens or apostrophes in their data, even though the formal way to spell certain cities or counties require them.  We use them! Some locations which require these characters are:

  • Winston-Salem, NC
  • St. George, UT (note: this is one of the only 'Saint' locations which is abbreviated because 'St.' is the official spelling).
  • Saint Mary’s county, MD
  • Prince George’s county, MD
  • Lee’s Summit, MO
  • O’Brien county, IA

Q: What is the difference between the Pro-ZIP Code base product and the Pro-ZIP Code Deluxe version?

A: Pro-ZIP Code is usually used in marketing and has one record per ZIP Code with the primary city for that ZIP Code. There are almost 43,000 records in this file.

Pro-ZIP Code Deluxe can have multiple cities per ZIP Code (when ZIP Codes cross city limits) and is primarily used in Order Entry applications where you key in a ZIP Code to find the correct city and state. It is also used in marketing where the correct city name is needed as well. There are over 57,000 records in this file.

Q: What format does the file come in?

A: The files come in a comma-delimited ASCII file. This is a standard format that will load into Microsoft Excel, Access or other databases. You can also get it in a pipe symbol delimited format, or a fixed-length format which is used by AS400 and mainframe computers.

Q: What is the file layout?

A: Please download a demo version of the file from our Download Page. With the demo, we include 'readme' help files which have the file layout and other helpful information such as how to load the file into Excel or Access.

County Questions

Q: Do you have county info? What file do I purchase to get it?

A: Pro-ZIP Code and Pro-ZIP Code Deluxe base products include the primary county name. If you need the county FIPS codes, then you would need to get the FIPS add-on product. If you need to know all of the possible counties a ZIP Code may cross over, you would need our Multi-County ZIP Code data.

Q: Do ZIP Codes cross county lines? Do you include all counties for a ZIP Code?

A: ZIP Codes often cross county lines. When it does, we include the primary county or that ZIP Code based on the total number of address. We do not include alternate county names in our Pro-ZIP Code and Deluxe products, but we do have them in our Multiple Counties per ZIP Code data.

Area Code Questions

Q: Do ZIP Codes cross area code boundaries? Do you include all area codes for a ZIP Code?

A: ZIP Codes also cross area code boundaries and we include the primary area code for that ZIP Code in the Pro-ZIP Code and Deluxe products. In our Multiple Area Codes per Zip product, we include all of the area codes which a ZIP Code covers, including overlays.

Q: When do you add new area codes in your data?

A: If an area code has just split within the last two months or so, we will not include that new area code. We wait at least two months after a split begins before we'll include the new area code in the product. The reason for that is because when a split begins, not everyone can dial the new area code. It usually takes over a month for all the phone companies to be programmed to use the new area code.

Additional Questions

Q: How often do the ZIP / postal codes really change?

A: U.S. ZIP Codes change sporadically. Most of the time there's just a few changes, but every now and then (especially around July 1st) there will be major changes. Canadian postal codes are undergoing some major changes, so each version usually has thousands of changes. Mexican postal codes also change, but sometimes they don't make the changes available to us more than once a year. We recommend that you update your files every time we send you new versions of the data.

Q: I have addresses, but I have some missing or bad ZIP Codes. How do I get them fixed?

A: If you have addresses with some bad or missing ZIP Codes, you can go to www.SemaphoreCorp.com and purchase a product called ZP4. That can clean up your database. We recommend that about once a year you purchase one of their additions (which is about $100.00) and run it through your database to clean up your addresses. Use our products to keep the data clean at data entry time.