When do you close? vs Until what time are you open?

I have just came across this situation.
At I can’t get rid of this question what should I say

1. when do you close
   or
2. until what time are you open?

it might sound really silly question,
but when you asking in your way,
which one would you prefer and what makes it more comfortable to say?

and it might be more silly to ask, but I am kind of wondering "when do you close" sounds a bit direct.

of course asking about the closing time is not a matter of polite or not, but it seems sounds just quick and might give the rude sense?

thank you in advance!