No doubt you’ve heard of the FAFSA, the application that every college requires in order for a student to get federal student aid. The CSS Profile is a separate, additional application that about 400 private colleges and scholarship programs require in order to award institutional aid (money that comes from the schools themselves).
The biggest difference between the two forms is that the CSS asks more detailed questions about family finances, including things like home equity. In the case of divorced parents, the FAFSA only requires information from the parent the student lives with most of the time, but the CSS must be filled out by both parents.
While the FAFSA is free, the CSS costs money to submit ($25 for the first school, $16 for each additional school), although you may qualify for a fee waiver if you received one for the SAT.
The CSS Profile, like the FAFSA, opens on October 1. You should submit it as early as possible but check each school for its submission deadline. Check here for a list of schools and scholarship programs that require the CSS.