<p>Right now, I'm a high school senior considering a single- or double-major in some combination of mathematics, computer science, and physics. (In the future, I'd like to pursue something like quantum computing or quantum loop gravity, though I might also end up in the computer science industry.)</p>
<p>If I wish to graduate in four years, when do I need to select my major(s)? (I know this probably varies by school, so feel free to generalize/provide a range/tell me to stop worrying/tell me to shut up.)</p>
<p>If you start by taking courses that prepare for all three majors, then you may be able to decide as late as your fourth semester, although that may not leave much room for out-of-major breadth courses or electives in your first four semesters (perhaps about one per semester). Those majors do overlap in some of their math courses (and possibly physics courses if the CS major at the school requires physics). If you enter with AP or college math credit which allows you to start in a more advanced math course, that can effectively give you extra schedule space later.</p>
<p>Note that choosing courses that prepare for all of the majors you are interested in is important, since some majors like physics have long prerequisite sequences. With such a major, if you do not start the prerequisites soon enough, you may not be able to graduate on time in that major.</p>
<p>I’m in a similar situation:</p>
<p>I’m planning on triple majoring in math, physics, and civil engineering. For me the decision basically has to be made by next summer when I plan to start taking courses in the math and physics major (linear algebra and quantum physics). This is the most important thing, you don’t want to take four computer science courses and then realize it’s not for you. It’s not horrible if that does happen but it makes things a lot tougher because it was essentially wasted time. </p>
<p>I came in with 46 credit hours already from AP exams and you probably will too depending on which college you go to, and this gives a lot of flexibility and room to play around with subjects and classes.</p>
<p>All in all, I would say you would need to choose probably by the end of your first year and depending on how accelerated you are maybe the end of the first semester.</p>
<p>@jimmyboy23 - Why are you doing a triple major. I understand wanting to take advantage of credits coming in (I had 45 when I started), but a triple major is… overkill. Given the general strictness of engineering accreditation, even with your credits I’m guessing you’ll have close to no elective slots outside of these major requirements. What do you hope to gain by doing all three of these majors? Employers are not going to care and graduate schools would rather you invest the extra time in research.</p>
<p>Usually by the end of sophomore year. At my school, you can after 39 credits but you have to after 54 credits (usually students take between 14-16 credits a year). This obviously varies from school to school and you should check the policies of each individual school. W&M is a school that encourages exploration and follows the liberal arts exploration philosophy despite being considered a national public university. But I would say anywhere from the end of first semester to the end of semester sophomore year is average, although there are some schools that require you to at least mention the major you are interested in when applying. Some majors are located in specific schools that you have to be admitted into.</p>
<p>But on the whole, do the research on the schools you are applying to and their policies on this front. On the whole though, don’t worry about it. Many students do not choose their major until after a a year and a half of school and many people change majors, so this is not an immediate decision you will have to make without taking college courses.</p>