What Is the Difference Between a ZIP Code and a Postal Code?

Although different countries use different address formats, most postal addresses in the world consist of similar elements. One of the most important elements in any address is the postal code or the ZIP Code. What is the difference between a postal code and a ZIP Code, and how to understand which one you need to use?

A postal code is a combination of digits and/or letters of the Latin alphabet, sometimes including hyphens or spaces, used for the purpose of sorting mail and speeding up its delivery. Each postal code designates a specific delivery area, making it easier to sort the mail by its final destination and streamline the delivery process.

The development of modern postal codes began in 19th-century England. As cities like London, Liverpool and Manchester grew, they were divided into postal districts to facilitate mail delivery, and each district was assigned a designation. By World War I, various large European cities had started to use postal district/zone numbers.

The first country to introduce modern postal codes not just for big cities, but also for small towns and villages was, somewhat surprisingly, the Ukrainian Soviet Socialist Republic in 1932. However, its experimental postal code system was discontinued seven years later. Germany introduced postal codes in 1941, followed by Singapore in 1950, and other countries eventually followed suit. Today, postal codes are used by at least 160 countries and territories.

Now that we know that a postal code is, let’s figure out how it differs from a ZIP Code. ZIP stands for Zone Improvement Plan; it is a standard term for the postal code system used in the United States and the Philippines. Postal zones were first introduced in large U.S. cities in 1943, but the ZIP Code system as we know it was implemented nationwide in 1963. Interestingly, its idea was first submitted by Robert Moon, a postal inspector from Philadelphia, in 1944, but it took almost two decades to actually make it work.

The U.S. ZIP Code system is used wherever mail is handled and delivered by the United States Postal service. This includes:

All U.S. states (contiguous states + Alaska and Hawaii)
U.S. territories (Puerto Rico, U.S. Virgin Islands, American Samoa, Northern Mariana Islands)
Army and Fleet Post Offices (APO/FPO)
Countries whose mail is handled by the USPS (Marshall Islands, Federated States of Micronesia, Palau)

A standard ZIP Code consists of five digits. The first digit represents a group of states, which may also include Army/Fleet Post Offices outside of the United States, and/or U.S. territories, and/or countries whose mail is handled by the USPS. The second and third digits designate a region or large city in that group, and the final two digits represent a group of addresses in that region or city. The USPS also uses ZIP+4 Codes where four additional digits represent a geographic area within the group of addresses designated by the standard five-digit ZIP Code, but their use is not mandatory.

The Philippines also uses a ZIP code system, but Philippine ZIP codes are different from their American counterparts. ZIP codes in the Philippines consist of four digits representing a specific locality, and their use is not mandatory, although it is highly recommended by the Philippine Postal Corporation (PHLPost).

So, the only major difference between a postal code and a ZIP code is that “postal code” is the general term for special codes used by postal services around the globe for the purpose of sorting mail, whereas “ZIP Code” is the standard term for a postal code in the United States and the Philippines. Basically, any ZIP Code is a postal code, but not all postal codes can be referred to as ZIP Codes. Similarly to the United States and the Philippines, other countries may have their own postal code names:

CAP (codice di avviamento postale) in Italy
CEP (código de endereçamento postal) in Brazil
Eircode in Ireland
NPA (numéro postal d'acheminement / numero postale di avviamento) in French- and Italian-speaking Switzerland
PIN (postal index number) in India
PLZ (Postleit‌zahl) in Austria, Germany, German-speaking Switzerland and Liechtenstein
Postal index in most former Soviet states
PSČ (poštovní směrovací číslo / poštové smerovacie číslo) in the Czech Republic and Slovakia

Whenever you address a letter, postcard, or package, you need to make sure the address includes the correct postal code (of course, if the destination country has a postal code system).