Country calling code

The 1-3 digit prefix that routes a number to its country: +1 for the US and Canada, +49 for Germany, +81 for Japan.

Country calling codes are assigned by the ITU and shared by every number in a country (or, for +1, a group of countries). Platforms read them to infer where a user is, which is why some sign-ups demand a local prefix and reject foreign ones.

Renting a number in a specific country is, practically, renting its calling code: the +49 in front is what a German-only service checks first.