Gapping is an informal financial aid term. It has to do with colleges offering less financial aid than they believe you need. After you fill out your FAFSA form (and possibly your CSS Profile), you will get a dollar amount called your E.F.C., or Expected Family Contribution. This is how much the government formula says your family should be expected to pay for college. The cost of a university, minus the EFC, is your need. If a university offers you less than your need in financial aid, then there is a gap. They’ve gapped you. You’ve been gapped. This is what gapping is all about.

For example: imagine that your E.F.C. is around $5,000 per year, and that you’ve been accepted to a school that costs $25,000 per year. Your need for that school is $20,000 per year. If their financial aid package, including grants, work study, and loans, only covers $15,000 per year, then your gap is still $5,000.

Why do schools gap students? The basic answer is that they haven’t got enough money in their budget to meet the full need of all the students they accept. They have limited funds, and they have to limit their spending. What this means is that, at a lot of schools, there’s quite an overlap between need-based aid and merit aid. Each school’s needs and approach is different, but the general idea is that they’ll offer larger aid packages, covering full need, for stronger students they really want to entice. Even if you don’t get a “merit scholarship,” you can often get a better “need-based” aid package if you’re a student they’re really trying to get to their school.

Isn’t it mean and unfair to accept a student and then offer them less financial aid than you know they need? Technically, no, it’s not unfair. Universities don’t have any obligation to cover the cost for people who can’t afford it. But it sure feels mean and unfair. To tell a prospective student “we’d love to have you here, and we’re going to offer you some discounts to make it more affordable…but not enough discounts” seems incredibly unfair. On the other hand, it seems equally mean and unfair to not accept a student just because you know that you can’t give them enough of a discount to make it affordable. Unless a university has enough endowment money to be able to offer need-blind admissions and meet full need, then that university has to balance between these two equally unfair things. There’s not a perfect answer.

There are ways to estimate what your gap might be at any school so you can plan. First, most schools publish their average percent need met. A basic Google search will pull this information up, and it’s listed in college information sites like Big Future and U.S. News. If I’m looking at schools in Arizona, I see that Arizona State University meets an average of 70% of need, the University of Arizona meets an average of 68%, and Prescott College meets an average of 74%. Please remember, though, that those are averages. It doesn’t tell you how much of your need will be met. The only way to know how much a college will cost you is to apply, get accepted, and get a financial aid offer. Universities also have financial aid calculators. They’re more specific to you and your needs than an average, but they are also often unreliable.

There are two ways to avoid having to work with gapping. The first is to have enough money to pay for college without any financial aid. Most people don’t fit into this category. The second is to apply to schools that meet full need—that is, they don’t gap. There aren’t a whole lot of them, and they’re pretty hard to get into, but if you’re interested in any of these schools, the fact that they meet full need should put them at the top of your list for applications. Still, remember a few things: of that small list, not all of them offer to meet full need without loans, and not all of them are need-blind when it comes to admissions. And none of them guarantee that they will have the same amount for your E.F.C. that your family thinks is reasonable.