018 is not a country code. Numbers inside a country start like this: Sumgayit (Azerbaijan), Bangkok/Nonthaburi/Pathum Thani/Samut Prakan (Thailand), Nis (Serbia), Adamantina - SP (Brazil). The first digit 0 is the trunk prefix for domestic calls and is dropped from abroad.
Have the full number? Check it in the number lookup.
| Area or operator | From abroad | Inside the country |
|---|---|---|
 Sumgayit · Azerbaijan | +994 18 … | 018 … |
 Bangkok/Nonthaburi/Pathum Thani/Samut Prakan · Thailand | +66 18 … | 018 … |
 Nis · Serbia | +381 18 … | 018 … |
 Adamantina - SP · Brazil | +55 18 … | 018 … |
| Alfredo Marcondes - SP · Brazil | +55 18 … | 018 … |
| Alto Alegre - SP · Brazil | +55 18 … | 018 … |
| 74 more in Brazil | ||
If a number starts with +, the first 1–3 digits are the country code. If it starts with 0 (8 in Russia and Kazakhstan), it is a domestic number: an area or operator code follows, and from abroad the 0 or 8 is replaced with + and the country code. The same digits can mean different places, so where the call came from matters.