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Zip Code

What is a Zip Code?

A ZIP code is the postal code system used in the United States by its Postal Service (USPS). ZIP stands for Zone Improvement Plan and was chosen since it implies that mail will delivered more efficiently by ‘zipping along’ if senders use the code when addressing items to mail.


How is a ZIP Code formatted?

Although the equivalent of the UK postcode system, ZIP codes are formatted in a different way, consisting of five numbers. More recently ZIP codes were further refined to include a hyphen and four additional digits to give a more specific location.

Validating ZIP Codes is an important process to check the format of postal addresses and subsequent correct delivery of mail items. This can be done using address validation software that matches address data against key reference data. This process is equally important outside the United States including the UK where addresses are matched against the Royal Mail PAF file to validate their accuracy.


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