I don’t know in Russian: How to say?

Some time ago, we have already looked into how to say I know in Russian.

Today, let’s see how to say I don’t know in Russian.

The simpliest and most straightforward way is to add не in front of the verb.

– Я не зна́ю.
– I don’t know.

However, there are other ways that are not directly translated as I don’t know, but in essence mean the same:

– Я не в ку́рсе.
– I’m not in the know.

– Я не представля́ю.
– I have no idea (lit.: I don’t imagine).

– Поня́тия не име́ю.
– I have no idea.

– Без поня́тия.
– No idea.

– Мне не изве́стно.
– I don’t know (lit.: It is unknown to me).

Among friends, you might also here this colloquial version:

– Отку́да я зна́ю?
– How do I know?

or:

– Отку́да мне знать?
– How do I know?

It is mostly used when someone is asked something that he or she is not really supposed to know.