Signal & Syntax · Numbers and formats

What Is a Numbering Plan?

A numbering plan is the national rulebook for phone numbers. The plan sets which ranges exist, each number's length and each range's use.

Also callednational numbering plan

Numbering Plan in Practice

Each country's regulator publishes the plan. Ofcom runs the UK plan. NANPA administers the plan shared by the US, Canada and Caribbean countries. The plan assigns ranges to mobile, geographic, toll-free and other services. A number outside every allocated range cannot be dialed.

Where ScoreMachine Fits

score.phone.validation
valid

valid returns whether the number fits an allocated range in the plan.

Related Terms

Numbering range A numbering range is a block of consecutive numbers allocated to one operator. Range holder The range holder is the operator allocated a numbering range. National destination code The national destination code (NDC) follows the country calling code. E.164 E.164 is the ITU-T standard for international phone numbers.

Read the Guide

Guide

E.164 Phone Number Format Explained

The parts of an international number and how to convert a list. Read the guide →

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