[General] How long are you going to stay here?

[Boris Tatarenko]

Hello.

Let's pretend my friend from Australia is going to spend his holidays in Russia, Moscow.
I want to ask him how long he wants to be here.

Is it polite way to ask:

"How long are you going to stay here?" or "How long will you stay here?"

P.S He hasn't arrived yet. I'm just wondering.

If my sentences are not natural, what will you say?

Thanks in advance.

 

[Rover_KE]

'How long will you be staying?'