College applicants have long had to wait until they were accepted before finding out how much aid they could receive and how much they’d have to pay — or borrow — to attend.

That’s about to change, just in time for college shopping season.

By the end of this month, colleges must post online a “net price calculator” that will estimate how much financial assistance applicants stand to receive. The accuracy depends on the quality of the information families provide, but it can help students rule out pricey schools before falling for them or even guide them to campuses they might have thought out of reach.

“Students and families really need to consider if a college is in their budget and it’s in their best interest to establish costs up front,” said Laura Martin, dean of admissions at Agnes Scott College, where the advertised, all-in cost is an intimidating $42,345 — but where qualified students also get merit awards worth about $15,000 a year. “I hope more people will realize that some of their dream schools are really in their budgets.”

The federal government required the device as part of the Higher Education Opportunity Act of 2008. Backers said the tool will allow families to understand costs earlier and clarify the difference between sticker price and what students actually pay. On average, college tuition was discounted by about 40 percent in 2010, according to national studies.

Winston Taylor’s son is a freshman at Grady High in Atlanta, and they’ve started looking at colleges. Price is a concern because Taylor’s son will be responsible for the bill. They’ve noticed that private colleges provide extensive aid and may be less expensive than public colleges.

“But it isn’t easy to find this stuff on the Internet, so this will be a tremendous help,” Taylor said. “I like that it will help my son take ownership. ... The more information we have about price, the easier it will be for him to decide what he can afford and where he should apply.”

Colleges must post the devices by Saturday. Many Georgia colleges have already done so.

The tool, which is also called financial aid calculator, is often found on admissions or financial aid web pages. Students answer detailed questions about the family’s income, savings, taxes and size. Then the program estimates how much aid the student is likely to receive, subtracts that from the college’s list price and approximates how much the student will owe. The estimates include tuition, fees, books and room and board.

Some calculators are more complicated than others and they ask a varying number of questions.

Stephanie Kratofil has a high school junior at North Gwinnett High and another daughter in her junior year at Georgia Southern University. She wondered how accurate the estimates are and what colleges will do with the private information students enter.

“It sounds like it will be great and could help families pick a college, provided it’s used correctly,” she said. “But what guarantees will we have that the discounted price is right?”

Warnings on the sites explain that the calculations are estimates and not binding. Although the program may ask students for their names and contact information, they don’t have to provide it to use the calculator. Also, students are not required to apply to the college to use the device.

An advocacy group, the Institute for College Access & Success, has argued colleges need to make the calculators easier to find and encouraged them to limit the number of required questions. If colleges ask detailed financial questions that require families to pull out old tax returns, some students will be discouraged from using the device, the group said in a recent report.

The calculator designed by the University of Georgia differentiates between in-state and out-of-state students and asks Georgia residents if they believe they will be eligible for the state’s merit-based HOPE scholarship. The program encourages students to complete the Free Application for Federal Student Aid that will determine if they are eligible for federal grants, loans or work study programs.

Agnes Scott’s version asks students to share their GPA and test scores so the program can determine what type of merit aid they might receive, Martin said. She said it’s safer to underestimate aid amounts.

“I don’t want to promise something and have to disappoint people later on,” Martin said.

Emory University launched its device about two weeks ago and it has done more than 200 estimates, officials said.

The new planning tool comes amid rising concern about student loan debt, which a new federal report says now exceeds credit card debt. Georgia students graduating from a four-year college in 2009 owed on average $16,568, according to data from the Project on Student Debt.

“It makes it harder to complain about the tuition bill if you know the cost up front,” Taylor said. “At least now you’ll know how deep a hole you’re about to dig for yourself.”