A country calling code is the number you dial after the + to route a call to a specific country. They are coordinated internationally so that no two countries clash.
How the numbering is organised
The world is split into nine zones, and the first digit of a code tells you the zone: 1 covers North America, 2 is mostly Africa, 3 and 4 are Europe, 5 is Central and South America, 6 Oceania and South-East Asia, 7 is Russia and Kazakhstan, 8 East Asia and special services, and 9 the rest of Asia and the Middle East.
Shorter codes, bigger networks
The busiest destinations got the shortest codes: 1, 7, then two-digit codes like 33 (France) or 44 (United Kingdom). Smaller countries have three-digit codes such as 212 (Morocco) or 351 (Portugal).
Finding the one you need
Every country page on this site gives you the exact code, how to format a number, and the exit prefix to use before it.
