What is the maximum length of a phone number in most countries?

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The maximum length of a phone number in most countries is governed by the international standard known as the E.164 numbering plan, developed by the International Telecommunication Union (ITU). According to this standard, the maximum number of digits allowed for a complete international phone number is 15 digits, which includes the country code, area or national destination code, and the subscriber number.

1. What Is E.164?
E.164 is the global standard for the structure and format of telephone numbers. It ensures that telephone numbers are globally unique and allows for consistent call routing across international borders. Under E.164, phone numbers follow this general format:

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+ [Country Code] [National Destination Code] [Subscriber Number]
The "+" sign indicates that the number australia mobile phone number list is in international format.

The country code can be 1 to 3 digits long.

The national number (area code + subscriber number) makes up the remaining digits.

The total length of all these parts combined must not exceed 15 digits.

2. Examples of Maximum-Length Numbers
While most phone numbers are shorter than 15 digits, some come close to this limit. For instance:

A phone number in India might be:

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+91 9876543210
Total: 12 digits (country code +91, 10-digit mobile number)

In China, a number could look like:

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+86 13800138000
Total: 13 digits

Even with 3-digit country codes, most numbers still don’t exceed 13–14 digits in total. However, the E.164 limit ensures room for future expansion and accommodates countries with complex numbering systems.

3. Why Set a Maximum Limit?
The 15-digit limit ensures:

Consistency: It provides a clear structure for telecom providers around the world.

Compatibility: Telecommunication equipment and software are designed with this maximum in mind.

Efficiency: It helps prevent excessive number lengths that could lead to dialing errors or system confusion.

Without a fixed limit, phone numbers could become inconsistent, causing problems in international communication and technical implementation.

4. Local vs. International Lengths
It's important to distinguish between local and international phone number lengths:

Local numbers within a country are often much shorter. For example, a landline in a small city might only require 7 digits.

However, when making international calls, you must include the country code and sometimes a city or area code, which increases the total number length.

In countries with large populations or many regions, such as the United States, Brazil, or Russia, the national numbers may be longer. But they still stay within the 15-digit international limit when combined with the country code.

5. Special and Emergency Numbers
Shorter numbers, such as emergency numbers (e.g., 911, 112) or service numbers (e.g., 123, 100), do not follow the E.164 format and are intended for internal use within a country. These are typically 3–4 digits long and not valid for international dialing.

Conclusion
In most countries, the maximum length of a phone number—when dialed in international format—is 15 digits, as defined by the ITU’s E.164 standard. This includes the country code and national number. The limit provides a globally consistent framework for telecommunications, ensuring reliable and scalable communication across the world. While everyday phone numbers are usually shorter, the 15-digit maximum ensures flexibility for growth and international compatibility.