What is E.164 Number Format?

E.164 is the international standard numbering plan for the worldwide Public Switched Telephone Network (PSTN). Developed to ensure global telecommunications consistency, it provides a unified format for expressing telephone numbers across different countries and networks.

How it Works

The E.164 format follows a simple formula to ensure every phone number is globally unique:

1. Country Code: Start with the international calling code (e.g., "1" for the US, "44" for the UK).

2. Subscriber Number: Append the individual phone number.

3. No Leading Zeros: Remove any "0" typically used for domestic trunk dialing.

4. Digit Limit: The entire string is limited to a maximum of 15 digits.

E.164 Formatting Examples

Why it Matters

E.164 is the primary standard used by global carriers like AVOXI. Because it eliminates ambiguity, it ensures that calls are routed correctly regardless of where they originate or terminate. Without this standard, a number dialed in one country might be misinterpreted or fail to connect when dialed from another.