International dialing codes

The basic pattern

An international number is normally represented in E.164 format:

+ country code + national significant number

Example: an Australian number written internationally becomes +61 followed by the national number without its domestic trunk 0.

E.164 numbers contain up to 15 digits, excluding the + sign. The + is a user-interface notation for the international access prefix; the actual exit code depends on the originating country and carrier.

Common country calling codes

This is a quick-reference subset, not a substitute for a live numbering database. Codes can represent shared numbering zones, territories, global services, or network services. Verify assignments against the ITU numbering resources and the current ITU E.164 assigned-code list.

Dialling rules that cause mistakes

• Do not blindly keep the domestic trunk prefix after adding the country code.
• Do not assume 00 works everywhere; use + in stored contacts where supported.
• Country code is not the same as area code, carrier code, or mobile network code.
• A valid-looking number may still be unreachable because of carrier permissions, routing, portability, time restrictions, or fraud controls.
• Store numbers in E.164 where possible; display them in a local format separately.