E.164 Numbering Standard

E.164 is an international standard defined by the ITU-T (International Telecommunication Union — Telecommunication Standardization Sector) that governs the format of global telephone numbers. It ensures every number is globally unique, enabling interoperability across international telephony systems.

E.164 Format Overview

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No spaces, hyphens, parentheses, or formatting characters in the number.

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E.164 Format Breakdown Example

Component Example Description
+ + International prefix indicator
Country Code (CC) 1 USA/Canada
National Destination Code (NDC) 415 Area/region code
Subscriber Number 5552671 Unique line number
Full E.164 Number +14155552671 Complete valid number

E.164 Format Examples by Country

Country E.164 Example Breakdown
United States +14155552671 +1 (CC), 415 (NDC), 5552671 (SN)
United Kingdom +442071838750 +44 (CC), 20 (NDC - London), 71838750 (SN)
Malta +35621234567 +356 (CC), 21 (NDC - fixed line), 234567 (SN)
Germany +493012345678 +49 (CC), 30 (NDC - Berlin), 12345678 (SN)
France +33123456789 +33 (CC), 1 (NDC - Paris), 23456789 (SN)
Australia +61298765432 +61 (CC), 2 (NDC - NSW), 98765432 (SN)

Incorrect vs Correct E.164 Number Formats

Incorrect Format Correct Format Notes
00441234567890 +441234567890 Use + instead of 00 for international prefix
+44 1234 567 890 +441234567890 No spaces allowed
+49-(30)-12345678 +493012345678 Remove hyphens and parentheses
1-415-555-2671 +14155552671 Must include + and country code
+33.1.23.45.67.89 +33123456789 Dots (.) are not allowed in E.164 format
0843486145 +33843486145 Must not include local dialling code 0 and must include + and country code

Why E.164 Is Important