What is NPA, NXX or NXX Codes

What is NPA, NXX or NXX Codes

When you order telephone numbers or consider to port an existing number, you might have heard about the common terms NPA and NXX. So what are these terms and how these terms are responsible to to form a phone number? Have a look at the informational guide on NPA and NXX below and feel free to share it with others on social media groups.

If we talk about the NPA and NXX codes then these are standard industry terms or two components of the North American Numbering Plan (NANP), used in North America countries like The United States of America, Canada, Costa Rica, Barbados, and many other Caribbean countries.

  • Length of Phone Number: 10 Digits
  • Raw Form of NANP: (XXX) XXX -XXXX
  • NPA, NXX, and Digits: (NPA) NXX – XXXX
  • Example of Phone No.: (305) 555-1111

All this is done for the local routing management in a telecommunications network to serve the calls on packed-switched network. A pdf is available here (bar code: US 2011 0085541A1) which you can download and read to know more how this actually works in real time environment.


NPA stands for a numbering plan area and considered as first part of a ten-digit North American telephone number.

You probably know it as the area code a three-digit number that identifies the telephone service region. While the area code identifies the telephone service region it’s possible for a single NPA to be present in more than one region.

For example: The 305 area code in Florida is present in the following centers – keys Biscayne, Miami, Homestead, North Dade, and Perrine. If you order a number in NPA 305 you can get a telephone number in any of those regions.

The NPA helps route telephone calls to the correct region before reaching the specific local phone number.


Now if we talk about about NXX, it stands for central office code or exchange office code.

It is three digit code that forms the second part of a 10 digit telephone number. It is just next to the NPA and provide the info regarding what’s the exchange office code.

For example: If you had the phone number (555) 101 – 1234 the NXX would be 101 which is an exchange code.

The central office code is assigned to a telecommunications provider or carrier, and it helps further route calls to the specific exchange serving a particular area or community.

Here’s video which can help you to understand more about the NXX mean and NPA mean in phone number:

It is worth noting that with the increasing demand for phone numbers, new area codes are periodically added or overlays are introduced to existing regions to accommodate the growing population and telecommunications needs.

This ongoing evolution helps manage the availability of phone numbers within the NANP.

So guys I hope now you have a clear idea about what is NPA and NXX codes. Still if you have any questions on NPA and NXX then you can use the free tools online that can find the npa nxx lookup by zip code / by address within few seconds.

Please let us know what do you think of the Npa nxx area code in the comments and don’t forget to share it with others on social media platforms.