How to tell if a phone number is landline or cell phone

Assuming the phone number was not ported from another type of service (ie switching a landline phone number to a mobile phone number), you should be able to determine the type of service using what is called the exchange code. This is the second set of three digits in a ten digit US phone number (ie. (xxx) xxx-xxxx).  The first set of three digits represents the area code, and the last four digits distinguish the user.

An entire phone number can be thought of as such:

(XXX) XXX-XXXX

Wherein:

(XXX) = Area code identifies the location.

XXX = Exchange code identifies the service provider and type of phone.

XXXX = User identifies who owns the phone number.

This categorization system is also known as the North American Numbering Plan (NANP) and if you visit the NANP administrations website you can find out more. Now, it is important to point out that with wireless number portability, these identifiers may not always be 100% accurate. In fact, it is likely that in the future these phone codes may not help much at all. For now, this will help identify many numbers as either landline or cell phone.