What Is a ZIP Code, and Postal Codes?

A ZIP Code is a 5-digit number. Introduced in 1963, the zip code was developed by the United States Postal Service® (USPS) to designate a single destination post office or mail delivery area. Due to the widespread use of postal codes, they were extended to nine digits in order to improve mail delivery efficiency. However, five-digit zip codes are used more frequently in people's daily lives. Like the US, most countries have their own postal code system names.

What's the difference between ZIP & ZIP+4?

Most people are familiar with the 5-digit ZIP code, which was later expanded to add an extra 4 digits after the dash to form the ZIP+4 code. A ZIP+4 code may correspond to a recipient in a city block, a group of apartments, or a single location. In essence, there is no difference between ZIP & ZIP+4. Generally, letters or mails only need to fill in a 5-digit zip code, but ZIP+4 pinpoints the address within a radius of several blocks in a more accurate way. Collectively, these additional additional numbers help to further improve the accuracy of mail delivery.

How the first digit of the zip code is assigned:

ZIP Codes Beginning With

States / Location

0XXXX

Connecticut, Massachusetts, Maine, New Hampshire, New Jersey, Puerto Rico, Rhode Island, Vermont, Virgin Islands, Army Post Office Europe, Fleet Post Office Europe

1XXXX

Delaware, New York, Pennsylvania

2XXXX

District of Columbia, Maryland, North Carolina, South Carolina, Virginia, West Virginia

3XXXX

Alabama, Florida, Georgia, Mississippi, Tennessee, Army Post Office Americas, Fleet Post Office Americas

4XXXX

Indiana, Kentucky, Michigan, Ohio

5XXXX

Iowa, Minnesota, Montana, North Dakota, South Dakota, Wisconsin

6XXXX

Illinois, Kansas, Missouri, Nebraska

7XXXX

Arkansas, Louisiana, Oklahoma, Texas

8XXXX

Arizona, Colorado, Idaho, New Mexico, Nevada, Utah, Wyoming

9XXXX

Alaska, American Samoa, California, Guam, Hawaii, Marshall Islands, Federated States of Micronesia, Northern Mariana Islands, Oregon, Palau, Washington, Army Post Office Pacific, Fleet Post Office Pacific

How to Read Zip Code:

1. The way to read the 5-digit postal code is that the first digit indicates the state or area of ​​the United States, ranging from 0-9.

2. The second and third digit: this set of numbers signifies a region within this group, such as a large city.

3. The fourth and fifth digits of the ZIP Code represent the area of the city or town.

For example, if a letter is received with a ZIP Code of 97001, the USPS can know that it's in Oregon (9), it's in Wasco county (70), and it's in the area of the Antelope (01).

Why accuracy of zip code and address information matters

Whether you're sending holiday cards to loved ones, sending documents and packages to customers requires valid address data and a zip code at the end of the address because UPS, FedEx, DHL, and many other shipping Companies all use zip codes to sort packages. If the zip code is wrong your package or letter will not be delivered accurately. So it is correct that the zip code can help the postal company quickly identify the geographical location, delivery point and mailing route.

How to write a U.S. envelope?

The first step is to write the reply address first:

The return address is three lines, the first line will be the sender's name. The second line writes the sender's detailed address, including the street address, please remember to write the house number. On the third line write your city, state and zip code. If for some reason your city and state information is taking up a lot of space, you can also put your zip code on the fourth line.

The second step is to write the recipient address:

You need to be more careful when writing the address and name of the recipient, and at least three lines of text are required here. The first line is also the recipient's name. When writing the recipient's name, pay attention to the title, and write the person's title and name in the middle of the envelope. On the second line, write the recipient's full address, including any associated apartment or suite numbers. The more detailed the better. The third line writes the recipient's city, state, and zip code, this information is the last line of the address.

ZIP Code Lookup | What Is My ZIP Code?

Performing a USPS zip code lookup is easy. For those who need to "Look up your own or your client's zip code?". Currently our data has more than 40,000 zip codes in the United States. What else can you do with our zip code finder? Find a zip code for any address in the United States. Follow your or a client's location to find the zip code closest to that point.