Question about class placement

<p>Hi, I am a senior and wondering that at stanford, can you test out of classes? Like, through placement exams, or are you just required to take some classes?</p>

<p>Because right now I am deciding whether I should just stick with Chem IB SL or switch to AP Chem or IB Chem HL, which can earn me credit. Stanford is one of the colleges I am applying to, and I can't find much information about this stuff on the Stanford website.</p>