The Concept and Story Behind the Zip Code

by Josh Biggs in Tips on 28th May 2019

The zip code is a convenient system of postal indexes currently used in the US. The system was specifically designated for faster and more convenient delivery of letters. Other countries in the world use postal codes or indices. It makes sense since countries have different size of the territory, so setting up an individual system that is purposeful for a specific administrative cause.

Zone Improvement Plan and other codes and indices are an open-source database. With a free zip code look up anybody can learn about the location of a person knowing their index and vice versa.

A 50-year-old Concept

The concept of coding areas by number first appeared in connection with the lack of expert workers as the aftermath of World War II. The system is tightly connected to the name of Robert Moon, who takes the credit for the invention. Even though postal services adopted the Plan only in 1963. However, Mrs. Moon states that her husband has actually offered the solution back in 1944.

Mr. Moon and his wife were both postal employees. The work was getting extremely hard as many qualified postal workers were recruited in the army. For non-qualified people, it was a challenge to deliver letters and packages. The delivery area kept on increasing and there was a need to introduce faster the system to help the non-qualified workers to perform better.

What Do 5 Digits Signify?

At the same time, the area of delivery was expanding. The initial system contained a number of denoting city and another number to index a state and needed perfection at that time. So, the revolutionary change of 1963 expanded the encoding to number representation:

  • area
  • regional post facility
  • local zone.

The new system was also helping airmail delivery.

Today a zip-code is represented by a set of 5 digits.

  1. The first digit signifies an area that includes several states, starting from zero and increasing a number moving from the east coast to the west.
  2. The next pair of digits indicate a more precise area within the initial defined segment by the 1st digit.
  3.  The final digits give information about the local post office.

Earlier the code contained some 4 more digits to specify an exact delivery address, like many systems around the world, have now. For smaller countries, neighbors residing in the next house may have a different index. It depends on the proximity to the postal office.

Within the time zip code lost its hyphenated specification of the area. The function was taken over by the sorting mechanics applied inside the US postal infrastructure.

Today, when sites ask about the delivery and say that they specifically want your zip code to deliver, this can mean that the delivery is available only within the US territory. It is the only country that uses this abbreviation, while other countries have different names.

Categories: Tips