E.164 number format

E.164 is an international standard developed by the International Telecommunication Union (ITU) that defines the format of telephone numbers for the global Public Switched Telephone Network (PSTN) and other data transmission networks.

Structure of an E.164 number

Maximum Length	15 digits
Country Code (CC)	One to three digits identifying the country
National Destination Code (NDC)	Code defining the geographic area, telecommunications operator, or type of service within the country
Subscriber Number (SN)	Unique number assigned to a specific subscriber

Example of a Singapore mobile number in E.164 format

Local mobile number	91234567
Country Code	+65
E.164 format	[phone]

In the international E.164 format, any leading zeros are removed, and all spaces, dashes, and parentheses are excluded.

Advantages of Using the E.164 format

Universality	A single format for all countries, ensuring compatibility between different networks and operators
Accuracy	Reduces the likelihood of errors in call routing and message delivery
Convenience	Simplifies the processing and storage of phone numbers in information systems

By following the recommendations of E.164, you will ensure reliable and efficient communication with customers around the world.