Understand Your Dial Plans

A dial plan defines a pattern of digits that users can dial to make calls inside or outside your business. Users within the business can call each other by using short extension numbers, as defined by their internal dial plan. Users can call external numbers based on an external dial plan that follows well-established practices for a region. For example, if your users are located in North America, their external dial plan is automatically set by the North American Numbering Plan.

Your 8x8 Work service comes with the default dial plan setup based on the country of your site. For example, a site located in the United States is set up with the North American Numbering Plan (NANP), which defines (3-digit area code + 7-digit phone number) when dialing within the country, and (011 + destination country code + phone number) when dialing internationally.

Users within the same business have the convenience of using short extension numbers to dial each other, regardless of where in the world they are. Short extension numbers are defined by the internal dial plan. In addition to the internal dial plan, customers can set external dial plans for the entire site or for an individual user. External dial plans define the dialed digit pattern used in specific regions, specify how to interpret phone number sequences entered by a user, and convert the sequences to normal outbound strings. For example, the North American Numbering Plan (NANP) defines a common dial pattern used by telephone networks within North America.

Using extension numbers, you can click or tap a contact from the contact directory and call your colleagues in the same office, in another city, or in another country.


  • Allow communication with users in the same office or another office using extension numbers.
  • Allow calls or chats with company contacts across sites and global offices.
  • Keep the qualified extension numbers unique across the phone system. The default extension number length is four digits, but can be overridden by the administrator at the site level.
  • Give each site a unique site code. The complete extension with a site code is used for reaching users across multiple sites.
  • Set sites within a phone system (PBX) with different site code lengths. The default site code is zero digits (or no site code), but can be overridden by the administrator at the site level.

Note: Do not assign extension numbers to your phone service that conflict with emergency numbers, or frequently used public numbers in a specific region such as: 911 and 988 in North America, and 112 and 999 in Europe.

Note: If you must define site codes, keep them the same length across all your sites.

Define an Internal Dial Plan

The following deployment sizes give you an idea of which internal dial plan you may need for your business:

Change Default Dial Plan

Depending on the size of your business, you may have one PBX, multiple sites, and many extension numbers.


Refer to the following frequently-asked questions for more information: