The Free Application for Federal Student Aid, better known as the FAFSA, is your passport to valuable sources of federal, state and college-based financial aid. But if you don’t fill it out, you could lose out on potential grants, scholarships and low-interest federal student loans. Even more troubling, research shows that high school students who don’t complete the FAFSA are less likely to enroll in college altogether.

That makes recent trends cause for alarm. By the end of the 2020-21 school year, nearly 5% fewer students submitted the FAFSA compared to the previous year, according to a report from the National College Attainment Network (NCAN), a group of nonprofit organizations focused on educational equity. That means about 102,000 fewer students have the opportunity to attend college affordably this year.

Here’s why pandemic-era FAFSA completion rates are bad news for students, and how to make sure you don’t miss out on free money for college.

Students graduating from high school in 2021 and planning to attend college in the fall experienced massive challenges in their junior and senior years. Pandemic-related disruptions including remote learning, job losses, health concerns and suddenly limited school-based resources like college counseling contributed to insufficient support for students.

As a result, throughout the 2020-21 school year, fewer students submitted a FAFSA than in the previous year, according to NCAN. That amounts to worse declines than the organization reported for the 2019-20 school year, when the Covid-19 pandemic began. Altogether, between 2019 and 2021, NCAN reports that about 270,000 fewer students filled out the FAFSA than anticipated.

In a survey of parents and undergraduate students conducted earlier this year, Sallie Mae uncovered a similar trend. Only 68% of survey respondents submitted a FAFSA in 2020-21, down from 71% in 2019-20 and 77% in 2018-19, according to its How America Pays for College 2021 study.

The FAFSA gathers financial information from students and parents in order to determine whether the student qualifies for need-based financial aid for college. If you’re eligible for need-based aid, that means you have multiple options to receive grants you don’t have to repay, including Pell Grants and student loans with low interest rates and fees, like subsidized federal student loans.

Even if you don’t qualify for need-based aid, fill out the FAFSA so you can get other types of federal student loans. These include unsubsidized federal loans, which have fewer perks than subsidized loans but similarly low interest rates and flexible repayment terms.

Colleges also use the FAFSA to distribute federal work-study funds and in many cases, institutional aid, meaning scholarships that come directly from the school. These can be awarded based on either financial need or personal accomplishments. Put simply, no one planning to attend college should skip out on the FAFSA.

But that’s just what is happening: When students don’t submit the form, they have far fewer ways to make college affordable if they attend school. And that’s a big “if.” According to NCAN’s research, a high school senior who submits the FAFSA is 84% more likely to enroll in college right away. That likelihood increases to 127% for students from the lowest-income families.

Put another way, when a student doesn’t submit the FAFSA, their chances of attending college the following school year plummets—especially when they’re most in need of financial support.

Some types of financial aid are first-come, first served. These include federal work-study funds and certain school- and state-based grants. The FAFSA opens up annually on October 1, and if you file the form as close to that date as possible, you have a better chance to receive money you don’t have to pay back. (The federal Pell Grant, however, isn’t awarded on a first-come, first-served basis; if you’re eligible, you’ll get the full amount you qualify for, up to $6,495 in 2021-22.)

The federal FAFSA deadline is much later than school and state deadlines. For example, for students attending college in 2021-22, the FAFSA first became available on Oct. 1, 2020. While the federal government doesn’t require you to submit the FAFSA to your college until just before you enroll, states and schools often have financial aid deadlines that are months earlier. As a result, you should aim to submit the FAFSA as close to October 1 as possible, even if you won’t enroll in college until a year or more later.

The FAFSA is available online at fafsa.gov and on the myStudentAid mobile app. To speed up the submission process, create a Federal Student Aid ID (FSA ID) in advance so that you can easily log in, save your work and sign the form. You must submit a FAFSA each year you’re in college, but once you’ve filled it out, you can renew the form thereafter rather than start from scratch.

If you’re a dependent student, your parents will have to submit their financial information, too. You’ll need access to a range of data including tax returns, your Social Security number, proof of untaxed income and more. The Federal Student Aid website lists the documents you should gather beforehand. Once you’ve completed the form, you’ll get a Student Aid Report, which offers a basic picture of the proportion of college costs your family will be expected to contribute.