Postal Code vs Zip Code: What Is the Difference?

Article Summary:

Both postal codes and zip codes are identification reference numbers that correlate to a specific location and direct mail services where to deliver packages. “Postal code” is the umbrella term for the numeric and letter system used in mail delivery around the world. The term “zip code” refers specifically to the coding system in the United States and the Philippines.

It’s a good thing postal codes and zip codes exist. Because of them, we can send and receive packages around the world within days. Though zip codes and postal codes are very similar, they do differ from one another. For one thing, zip codes apply within the United and the Philippines, whereas postal codes apply internationally. By the end of this article, you will understand the similarities and differences between these two sets of codes.

Zip code defined

ZIP is an acronym for Zone Improvement Plan. The zip code system is primarily used by the United States Postal Service (U.S.PS). A zip code is a numeric code that postal services use to identify exact recipient locations for easy and prompt delivery. Each number in a zip code indicates a specific subregion. The main goal of zip code data is to maximize the efficiency of delivering mail.

There are currently 41,694 zip codes in the United States. A single zip code defines an average area of 90 square miles and an estimated average population of 8,152.

Postal code defined

Postal codes refer to the alphanumeric or numeric codes that identify the exact locations of postal addresses. The postal code system is an automatic mail sorting system used by many countries around the world. A postal code contains both a regional and a specific identification code. The format of postal codes can vary slightly by country. Similar to zip codes, postal codes help post offices and mail carriers identify the exact delivery location for mail.

Differences between a postal code and zip code

Zip codes and postal codes are very similar. The terms are often used interchangeably, but they are not the same. Postal codes are not all zip codes, but zip codes can be categorized as a type of postal code. The main differences between the two are where and how they are used.

Country of adoption

The zip code system operates in the United States of America and the Philippines. The postal code system operates in the United Kingdom and most other countries. Just like the U.S. uses zip codes, other countries have unique postal code systems.

This difference doesn’t mean it is impossible to send mail from the U.S. to the U.K., for example. The zip code and postal code systems can interact with one another. You probably wouldn’t notice the difference when sending mail between a zip-code and a postal-code country.

Year of inception

The United States implemented zip codes in 1963. Countries around the world started to use postal codes in 1959.

What did they do before this? Initially, the mailing system wasn’t as regulated. Mail was hand-sorted and delivered based upon a street address, city, state, and country. There were no zip codes or postal codes.

Some countries started using rudimentary codes before the official zip code and postal code systems were born. For example, postal zones came before zip codes in the United States and were used from 1943 until 1963.

Objective and usage

Postal codes and zip codes have a similar objective. The main purpose of both coding systems is to provide location identification information to postal services. Both are used to define exact locations for efficient mail deliveries.

One difference between the two is that postal codes are usually used for census and route planning. However, first responders typically use zip codes to quickly track the location of an emergency.


Zip codes contain only numbers and, sometimes, punctuation. Typically, zip codes contain 5–9 numbers. An example of a U.S. zip code format is 12345-6789. The first five numbers of a zip code are always used. The last 4 numbers following the hyphen can be used to further specify the location of a postal address, but are usually not mandatory.

Postal codes can contain either only numbers or both numbers and letters. A postal code can also contain punctuation and spacing. For example, a U.K. postal code could look like this: AB12 2XX. Lengths of postal codes can vary depending on the region.

With U.S. zip codes and postal codes in other countries, the code’s formula contains a specific sequence of numbers that indicate location information from the area, to the subarea, down to the most specific district.

Pro tip — The Internet makes it easy to find zip codes and postal codes. If you want to find out the postal code or zip code for an address or area, just type the city or street address into your browser and the code should come right up!

Key takeaways

  • Zip codes and postal codes are similar, but they are not exactly the same thing. They have differences in their country of adoption, year of implementation, format, and usage.
  • ZIP stands for Zone Improvement Plan, and it is mainly used in the United States. The zip code system is a 5–9 numerical code classification system that indicates the exact postal region.
  • Postal codes are used to sort mail in other countries. Just like zip codes, they indicate exact locations for mail to be delivered to. A postal code’s formula varies by country.
  • It is easy nowadays to find your zip code or postal code with a quick Internet search. You just have to know part of your address.


How do I know my postcode?

Find your postcode by typing your postal address into an Internet search engine (most browsers do this for you automatically when you type search terms in the address bar) or a postcode website. You can also contact your local post office.

How do I know my zip code?

You can find your zip code by entering your delivery address into the United States Postal Service zip code lookup site.

What is the use of postcode?

Postal codes are used in the United Kingdom and many other countries as location identification. Postcodes help to efficiently sort mail and deliver it to exact locations as quickly as possible.

What is the use of a zip code?

One zip code defines a specific region. Mail is classified by the zip code of its delivery address. Postal services use zip codes in the United States and the Philippines to efficiently deliver mail.

Is the postal code the ZIP code?

A zip code and a postal code are not the exact same thing, although they are related. Postal codes are not always zip codes. Zip codes are a form of postal code.

More to learn: If you need to find your billing zip code associated with your debit card, read this article by SuperMoney next. If your pressing concern is how to mail checks safely, read this post instead.
View Article Sources
  1. Look Up a ZIP Code — United States Postal Service
  2. The Untold Story of the ZIP Code — Inspector General of the United States Postal Service
  3. This Month in Business History: ZIP Code Introduced — Library of Congress
  4. What’s the difference between Zip Code and Postal Code— Nuance
  5. How To Mail a Check Safely and Can You Fold It? — SuperMoney
  6. Where Is the Zip Code on a Debit Card? — SuperMoney