How strongly does your decided major affect your admission into a University?

Great question. Guidance counselors and other educational experts will vary in opinions regarding this question. Some often say listing a major is a big advantage, that it can't hurt, while others will argue that it will hurt your application more than help it.

You can major in Finance and still be a MIT student, so this does not hurt you. However, if you are going to declare a major, do not do it for the sake of getting into your dream college. Don't declare a major in Finance if it clashes with the information on the rest of the application. Colleges know that some students who declare a major will end up switching their major during college. If you have an interested major that ties together with your academic success in a particular subject or related extracurricular activity, go ahead and declare the major.

College Admissions want to know who you are, so if you decide to declare a major, make sure it clearly conveys your interest and who you are. Otherwise, there's no huge impact if you do not declare a major on your college application. You have a little time to figure this out after you matriculate into college.

In short: colleges are all different, but choosing a less popular major at your colleges of interest can actually be a good thing. You may have heard the story about colleges wanting a tuba player and so admitting a student who can fill that niche. That's somewhat apocryphal, but the idea still applies to less popular majors. The colleges want to fill those majors!

Also: research your colleges and programs of interest to determine whether you will be directly admitted into a major, or directly admitted into the college/university, and if you will have to apply for admission to your major once you've been accepted (or even enrolled for a year or two) at that school. Most universities will admit you regardless of your preferred major if your application is strong. Some of those schools won't admit you directly to your major, however. They'll expect you to apply for admission to that program once you have shown your quality in college.