help desk software
 In Address Verification

zip plus 4

If you are reading this blog post you have asked yourself at least once what are ZIP+4 Codes. To answer this question, we should first take a step back. ZIP Codes were introduced by USPS in 1963 with the aim of making the mail travel faster (“zipping along”) when senders use them. Initially, ZIP codes consisted of five digits. However, with time, the US population has significantly increased and 5-digit codes were no longer accurate enough. Thus, in 1983, USPS introduced ZIP+4 codes. Known also as “+4 codes”, ZIP+4 codes add another layer of precision to the standard code that was comprised of five digits.
In a few words, you can break down a nine-digit ZIP Codes in two distinct parts:

  • The first five digits that point to a specific delivery area or post office
  • The last for digits that indicate a delivery area down to a few blocks radius.

How ZIP Codes are Used

Let’s say you are living in San Franciso and would like to mail a letter to one of your friends in Atlanta. The carrier that firstly receives the letter, that is in San Francisco, doesn’t have to know the exact delivery address. All that he is interested to know is to which mail carrier should he forward the letter. And here is where ZIP codes help.

USPS usually assigns ZIP Codes to a post office. In other words, every postal office has a ZIP code as its mailing address. Of course, there are larger post offices that are able to handle more than one ZIP code. However, each post office has at least one ZIP code assigned to it.

So, USPS created 9-digit ZIP Codes to ensure fast and accurate mailings. They indicate the actual path the mail should travel and usually they narrow down to somewhere between ten to twenty homes.

Benefits of ZIP Plus 4


Initially, 5-digit ZIP codes were welcomed by everybody because they divided the U.S. into a few individual “zones”. This greatly simplified the way USPS sent packages and letters. However, as the population grew and scattered, 5 digits weren’t enough to uniquely identify an address. 

Just think that, according to a recent USPS study, around 40 million Americans move every year. Obviously, this brings an increased number of undelivered mailings due to incorrect shipping addresses.

zip + 4
So, USPS deemed no less than 4.3% of the 158 billion mailed items in 2013 as Undeliverable as Addressed (UAA). 

With ZIP Plus 4 Codes, you can significantly increase the delivery speed and accuracy. For example, they speed the overall delivery process by one or even two days.

Another important benefit of ZIP+4 Codes is that they require validation; the way it works is that you can be sure an address exists if it has a ZIP+4 Code assigned to it. You should not forget that they can help with getting bulk mailing discounts.

Why use WinPure Clean & Match Enterprise with Address Verification?

You should be aware that ZIP Plus 4 Codes are based on the actual delivery routes. This means that they actually change pretty often. In fact, USPS can update a ZIP+4 Code as frequently as once in two months. This means that it would be incredibly time-consuming to add this codes manually.  Thus, in order to enjoy the full benefits of ZIP Plus 4 Codes and mail faster and with increased accuracy, it is best to use software that is always up to date and can process high amounts of data.

Our award-winning WinPure Clean & Match Enterprise with Address Verification is capable of checking the deliverability of every address in the U.S. Moreover, we designed it in such a way that you can easily integrate it with all your existing data sources: marketing/mailing lists, databases, spreadsheets, CRM’s and so on.

Try WinPure Clean & Match Enterprise with Address Verification today and discover why large companies such as Bank of America, Vodafone, McAfee, Hewlett-Packard, and Emirates are happy to use our leading data cleansing and data matching software.

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