The Country Codes That Trip People Up

Trunk prefixes

Many countries put a digit — nearly always 0 — in front of a number when it is dialled domestically. It tells the local network that a long-distance number follows. Internationally it is meaningless, and the country code takes its place.

So the conversion is a replacement, not an addition. Remove the leading zero, then prefix the country code.

• United Kingdom 07911 123456 becomes 447911123456
• Morocco 0612 345 678 becomes 212612345678
• France 06 12 34 56 78 becomes 33612345678
• Germany 0151 23456789 becomes 4915123456789
• UAE 050 123 4567 becomes 971501234567

Countries with no trunk prefix

Spain, Italy and the United States, among others, have no trunk prefix at all. Their numbers are used unchanged after the country code, which is why copying a Spanish number into a link usually works on the first attempt and a British one usually does not.

• Spain 612 345 678 becomes 34612345678
• United States (415) 555-0132 becomes 14155550132
• Italy 312 345 6789 becomes 39312345678 (the leading 3 is kept)

Italy, the exception to the exception

Italian mobile numbers begin with a 3 that looks like a trunk prefix and is not. Strip it and the number becomes invalid. This is the single most common mistake made by people who have learned the remove-the-leading-zero rule and apply it everywhere.

Shared country codes

The United States and Canada share +1; several Caribbean nations do too. Kazakhstan and Russia share +7. The country you pick from a list does not always uniquely determine the code, and the code does not uniquely determine the country — but for building a link only the digits matter, so this is a labelling curiosity rather than a functional problem.

The shortcut

You can learn these rules, or you can pick a country from a list and let a tool apply them. The link generator on this site does the conversion in your browser, and the Click to Chat app does the same thing on iPhone with the country selector on its main screen.