The E.164 standard! defin by the ITU-T! outlines the international public telecommunication numbering plan. This standard dictates that a full international telephone number should consist of digits only and have a maximum length of 15 digits. This length includes the country code! follow by the national destination code (which can include area codes or network codes)! and finally! the subscriber number. The first digit after the plus sign (indicating international format) must be between 1 and 9! as no country code starts with 0.
For example! a typical E.164 formatt number might look like where:
- + signifies the international format.
- CC is the country code (1 to 3 digits).
- represents the National Destination Code and Subscriber Number combin! with a maximum of 12 digits (15 total digits – 3 country code digits).
This 15-digit limit is a global constraint design to ensure interoperability and efficient routing across the world’s public switch telephone networks (PSTN).
Countries with Longer National Numbering Plans
While the international standard caps at 15 digits! some countries have national numbering plans where the subscriber part of the number is quite long! or where dialing within the country involves a combination of codes that feel longer.
For instance! according to some sources:
- North Korea has been list with a maximum phone number length of 17 digits (including internal routing codes)! which could japan phone number list potentially exce the E.164 recommendation if interpret as a single number. This might imply specific internal dialing sequences or variations in how numbers are present locally versus internationally.
- Australia has numbers that can go up to 15 digits when including the country code! which aligns with the E.164 maximum.
- Japan! Germany! and Swen often have national numbers that! when combin with their country codes! can reach 13 digits. For example! a Japanese number might be 9-10 digits locally! and with a 2-digit area code! it can become quite long! fitting within the 15-digit international limit.
- China typically uses 10 or 11 digits for azerbaijan business directory national numbers (excluding the initial zero us for domestic long-distance dialing). When the country code +86 is add! these numbers also fall well within the 15-digit E.164 limit.
It’s important to note that the “longest phone number” can be ambiguous. It could refer to:
- The total digits in an E.164 international number: This is capp at 15 digits.
- The length of a national subscriber number plus area code (excluding the country code): This varies significantly by country! with some having numbers up to 12 or 13 digits.
- Specific internal dialing sequences: Some know your audience inside out countries might have unique service numbers or special access codes that! when combin with a subscriber number! create a longer sequence for domestic dialing.
Why Do Numbers Vary in Length?
The variation in phone number lengths globally is due to several factors:
- Historical Development: Different countries develop their numbering plans independently before strict international standardization.
- Population Density and Demand: Countries with larger populations or higher demand for phone lines often require longer subscriber numbers to ensure uniqueness.
- Structure of the Network: The way a country’s telecommunication network is design (e.g.! how many area codes! how many exchanges) influences number length.
- Services Offer: The proliferation of mobile phones! VoIP services! and special service numbers (like toll-free or premium-rate lines) can influence the structure and perceiv length of numbers.
The Longest Practical Phone Number
In practical terms! the longest phone number you would typically dial to reach a standard subscriber anywhere in the world will adhere to the 15-digit limit of the ITU E.164 standard. While some national plans might have sequences that are close to this limit or even slightly exce it for internal purposes (like North Korea’s purport 17 digits)! these are exceptions or specific domestic dialing patterns rather than universally routable international numbers. For any global communication! the 15-digit standard is the practical maximum you’ll encounter.
