What Is a Mobile Numbering Plan?

Mobile phones are central to what is a communication in the modern world, and every mobile number is structured according to a system known as a mobile numbering plan. This system defines how mobile numbers are assigned, formatted, and used across various countries and networks. While users rarely think about the logic behind a mobile number, the numbering plan is vital for network routing, billing, identity verification, and regulatory compliance.

This article explores what a mobile numbering plan is, how it works, its components, and its global implications.

What Is a Mobile Numbering Plan?

A mobile numbering plan is a structured system used by telecommunications authorities to allocate mobile phone numbers within a specific country or region. It defines:

• The format and length of mobile numbers.

• The prefixes or codes used to identify mobile networks.

• The range of numbers assigned to specific carriers or services.

• Rules for international dialing, mobile number portability, and special service numbers.

Each country develops its own numbering plan, typically regulated by a national telecom authority (e.g., the FCC in the United States or OFCOM in the UK) in coordination with international recent mobile phone number data standards set by bodies like the International Telecommunication Union (ITU).

 Components of a Mobile Numbering Plan

Mobile numbering plans vary by country, but they generally follow a common structure. A complete mobile number often includes:

1. Country Code (CC)

• This is the international dialing code assigned by the ITU.

• Example: +1 for the USA, +44 for the UK, +91 for India.

2. National Destination Code (NDC) or Area Code

• Used within the country to the importance of accurate data collection direct calls to the correct region or mobile network.

• In mobile numbering, this may indicate the mobile network operator.

3. Subscriber Number (SN)

• The unique number assigned to an individual or business.

• Combined with the NDC to form a unique number within the country.

Types of Numbering Plans

There are two main types of numbering plans globally:

1. Closed Numbering Plan

• All phone numbers have email data a fixed number of digits.

• Common in countries like the USA and Canada (North American Numbering Plan – NANP).

• Example: 10-digit mobile numbers.

2. Open Numbering Plan

• Numbers may vary in length depending on the region or service.

• Found in many European and Asian countries.

• Often used with trunk prefixes for domestic dialing.

 Number Ranges and Network Identification

Regulators often assign specific number ranges to different mobile operators. For instance:

• In the UK, mobile numbers starting with 07 are typically assigned to mobile networks.

• In India, 98, 99, and other prefixes are reserved for major mobile operators.

Although Mobile Number Portability (MNP) allows users to keep their number when switching carriers, the original prefix may still indicate the initial network.

International Numbering and the E.164 Standard

The E.164 standard is an ITU recommendation that defines the international format for phone numbers:

• Maximum of 15 digits.

• Includes country code but no trunk prefix (like 0).

• Format: +[Country Code][National Number]

This format ensures numbers are globally unique and compatible across international networks and systems.

Mobile Number Portability and Numbering Plans

Mobile Number Portability (MNP) allows users to retain their number when switching networks. While MNP promotes competition and consumer freedom, it also complicates the link between number prefix and carrier.

As a result, businesses and APIs can no longer rely solely on number prefixes to determine.