How many interviews will I have at Oxford?

Anywhere between one and many! It depends on the type of your degree, the decisions of the admission officers, and the amount of colleges that consider offering you a place. If you're applying for a joint school or a degree with two clearly defined parts (e.g. English&Classics, French&German respectively), you will have at least two interviews. You also might or might not have a follow-up interview at your college - this usually happens if the admission officers have not met you at previous interviews, or if they want to get a second impression. If you are being considered by more than one college, you may have a full set of interviews for each. In short, the only way to really know for sure is to arrive for interviews and find out for yourself!