How to Avoid the Dreaded Dropped Zeros of ZIP Codes

Pro Tips on Exporting: The Dreaded Dropped Zero on ZIP Codes

Mailing directly to your preferred client lists is a great technique for far-reaching, well-targeted marketing. Sending direct mail to lists of property owners to their home address often means that your marketing outreach will be delivered all over the nation, not only within the state where your preferred properties are located.

This is especially true in instances where small businesses are targeting properties that are listed as “Non-Owner Occupied” in an attempt to reach the “Absentee Owners” at their home address.

For example, John and Jane Smith own a rental property in California that is of interest to your business, but they live full-time in Connecticut. To reach out and connect with them, your direct mail piece with messaging pertaining to their property in California will be sent to them in Connecticut.

There are 3,669 zip codes in the U.S. that begin with a zero, most of which are located on the east coast.

When a list is exported as a .csv file and contains a zip code beginning with a zero, it is recorded within the .csv as “01234” because zip codes are five digits. Zip+4 is a more common way to record zip codes, “12345-1234.” The first five digits indicate the destination post office or delivery area and the Zip+4 code represents a specific delivery route.

Importing .csv files that contain zip codes leading with zeroes can lead to the dreaded dropped-zero problem. Some programs, most notably Microsoft Excel, treats the “01234” as an integer, not a string, so it drops the zero and leaves you with a four-digit zip code, which is not good.

Postal services, especially the USPS, will not deliver to malformed zip codes. All zip codes must be five digits, even if the first, second or third zeros are dropped.

When sending a direct mail campaign, it’s always best to inspect your list, sort by zip code – smallest to largest – and validate that all zip codes have five digits. If you happen to find three or four-digit zip codes, you will need to change the column format to a “00000 zip code” and add back the leading zeros before printing your labels or uploading codes to a direct mail service.

Most direct mail services will reject addresses with malformed zip codes. If your list of 1,000 addresses contains 100 malformed zip codes with dropped zeros, only 900 will be uploaded. This is true with our print partners.

The dreaded dropped-zero on zip codes is a problem well known to marketers who frequently send direct mail collateral, and dates back to 1979, when the first consumer spreadsheet program viewed important zip codes as integers, not strings.

The best way to preserve leading zeros in Excel can be found here.