How International Dialing Codes Work
An international call usually combines an access prefix for the network you are calling from, the destination country calling code, and the destination number. These parts are easy to mix up because the access prefix can vary by origin.
The parts of an international phone number
The country calling code identifies the destination numbering plan. After it comes the destination's national significant number, which may include an area or regional code and the subscriber number. The length and structure of that national number vary by country.
ITU-T Recommendation E.164 describes the international numbering plan. It distinguishes the international country code and national number from dialing prefixes used to place a call.
What the plus sign means
The plus sign is the standard notation for an international number in the format used by ITU-T E.123. It stands in for the international access prefix required by the network you are using; it is not itself a country code.
A mobile phone may translate the plus sign into the right access prefix for its current network. On a landline, office phone, or restricted calling plan, you may need to dial an access prefix or an outside-line number instead. Check the carrier's instructions when a call does not connect.
A reliable way to prepare the number
- Confirm the destination country code: Use a current numbering reference and verify the destination rather than guessing from a familiar area code.
- Find the destination's international format: Follow that country's published numbering plan. A domestic trunk prefix may be omitted in the international format, so do not automatically copy every digit from a local dialing example.
- Use the right access method for your line: Use the plus format on a device that supports it, or the international access prefix and any outside-line digit required by your service.
- Check rates and restrictions: International calls may be blocked or billed differently by your provider, even when the number is formatted correctly.
Common dialing mistakes
- Assuming one international access prefix works from every country or phone system.
- Adding a domestic trunk prefix that should not be included in the international number.
- Treating the country calling code as the complete number instead of adding the destination's national number.
- Assuming an online lookup can confirm that a number is active or that the call will be free.
Use a directory as a reference, not a connection guarantee
TheCodePlaza's calling guide and dialing-code directory can help identify the published codes and format a number for review. They do not place the call or verify carrier access, current assignment, availability, or charges. For important calls, confirm the number with the recipient and check your provider's terms.
Common questions
Is the international access prefix part of the country code?
No. The country calling code is part of the international number. The access prefix is selected by the network you are calling from and can vary by origin.
Can I use a plus sign from any phone?
The plus sign is standardized international-number notation. Whether a particular phone or calling service accepts it directly depends on that device and network.
Should I always keep the first zero in a local number?
Not necessarily. Some national plans use a domestic trunk prefix that is not included in the international form. Check the destination country's current instructions instead of applying a universal rule.
Sources and further reading
- ITU: Recommendation E.164 — The international public telecommunication numbering plan — Defines the international public telephone numbering plan and its country-code and national-number structure.
- ITU: Recommendation E.123 — Notation for national and international telephone numbers — Specifies the plus sign as the international-prefix symbol in the written form of an international telephone number.