In addition to buying a house or car, paying for a child’s college education is among the biggest expenses many Americans incur in their lifetime. Fortunately, many families don’t have to fund it all themselves.

How much your child’s degree will ultimately cost depends on many factors, especially where they choose to go to school, how much your family income is, and what your assets are. But all roads to that calculation start at the same square one, and it’s called the FAFSA.

The Free Application for Federal Student Aid (FAFSA) is a standardized form used by the federal government, as well as many states and universities, to determine your family’s capacity to pay for your child’s education, and by extension, how much assistance you’re eligible to receive.

Virtually every student should submit a FAFSA, even if you think you make too much money to qualify for aid. That’s because the FAFSA doesn’t just target grants, but also your eligibility for low-interest federal student loans, which are available to almost everyone and are a much better deal than private student loans.

It’s critical to be aware of the FAFSA’s timing. First, know that you’ll need to file it ahead of every year your student will attend college. Second, the filing window opens October 1 of the prior year. So for a student starting college in the fall of 2024, you would file their first FAFSA as early as Oct. 1, 2024.

Filing as close to October 1 as possible is important, as many colleges dole out aid on a first come, first served basis, using students’ FAFSA filing date as their position in the queue. Also, some states have their own deadlines, so you’ll want to make sure you file in time to be considered by your state as well.