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What Is a ZIP Code and How to Check It? Manual vs. Automatic Zip Code Checks

February 26, 2021
Inkit Team

What Is a ZIP Сode?

A ZIP code is a five-digit code that United States Postal Service uses to designate delivery routes and service areas. Based on the ZIP-code system, letters reach specific facilities for sorting mail. Sorting enables mail carriers to deliver high volumes of mail more quickly and easily.

In the United States, ZIP codes are used to deliver domestic mail. There are usually no ZIP codes for mailing to other countries.

A ZIP code is indicated alongside the address after the name of the city and state abbreviation. For example, the correct address format will look like this:




In this address, 70112 is a ZIP code.

How to Read a ZIP Code

The first three digits represent the sectional center facility connected with this code (e.g., codes starting from 1 mean New York). The fourth and fifth digits stand for the area of the city or town. 

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What is the zip code for…X? ZIP code Lookups and Map

If you want to know the ZIP code for a specific geographic location, you can use ZIP code lookups or the US map. ZIP code lookup tools automatically generate ZIP codes based on an address or city & state data. They can also do a reverse search and find cities by  ZIP code.

To manually find a ZIP code, use one of the following ZIP code lookups:

To view what is the ZIP code for a US region, use this map:

zip codes map

Automated address data enrichment

If you run a business that depends on mail delivery, you will need to format and verify thousands of addresses automatically. Manual ZIP code lookups won’t work.

Inkit Verify is one of the automated address validation tools you can adopt. It autocompletes shipment addresses as users type them and also verifies your existing records. This tool adds ZIP code details if necessary and detects incomplete addresses. As a result, your address database is always updated and accurate.


  • Do ZIP codes represent geographical areas?

Even though sometimes ZIP codes and geographical areas overlap, ZIP codes don’t represent regions. ZIP codes are just delivery routes or groups of addresses.

  • Is postal code the same as ZIP code?

A postcode is a generic term, whereas the ZIP codes are used only in the US postal system. Besides, postal codes can consist of both numbers and letters, whereas ZIP codes include only numbers.

  • ZIP codes vs. ZIP+4 codes: What’s the difference?

ZIP+4 is a new ZIP code standard introduced in 1983 to enhance the accuracy of mail delivery. It uses the standard five-digit ZIP code plus four additional digits. These digits signify a small delivery area (e.g., street, city block, PO box). ZIP+4 codes are not mandatory and are usually assigned automatically at the mail sorting centers. Therefore, if you want to send a letter, a basic ZIP code will be enough for a post office to complete the delivery.

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