How landline codes are built, why 495 and 499 both mean Moscow, and how to dial them from abroad.
Three-digit codes
Most regional centres have a three-digit code: 812 for Saint Petersburg, 343 for Yekaterinburg, 383 for Novosibirsk. The subscriber number is six or seven digits, so the whole number is ten digits after the 8.
Moscow and its two codes
Moscow has 495 and 499 — both are the city, split by capacity. A Moscow number can start with either, and the dialing rules are the same.
Four- and five-digit codes
Smaller towns have four or five digits, and the subscriber number is correspondingly shorter. That is why the total length stays at ten digits: the code takes what the local number does not.
Dialing from abroad
Drop the leading 8 and the trunk prefix: +7 495 123-45-67. Never keep a leading zero in front of the city code.
How to find a city by code
Every area code has a page listing the cities that use it and the operators working there. If a number's code is unfamiliar, start from the code page rather than guessing the region.
See also: finding a city by its code, why numbers start with 8.