The initial withdrawal fee is shown on the BTC withdrawal page.
*As of July 18, 2017, the initial whithdrawal fee is 0.0005 BTC.

*The actual fee paid to miners can be higher or lower than the specified rate.
*You might want to set the fee as higher than the initial rate if you are in a hurry.
*It is possible to set the withdrawal fee as smaller than the initial rate,
but then the approval process in the network might take several days or weeks.