You can fill out a CSS Profile application as early as Oct. 1 for the upcoming school year. Ideally, you should aim to complete your profile as close to the application opening date as possible to increase your aid potential. The College Board recommends submitting your profile no later than two weeks prior to a college’s priority filing date for financial aid applications. As far as the cutoff date goes, each institution sets its own deadline regarding when you can submit your completed CSS Profile application. Often, these deadlines fall somewhere between Jan. 1 and March 31. You should check with individual schools or scholarship programs you’re interested in to learn more about any specific deadlines that could affect you.