St. Mary's College of Maryland has only locked in about two-thirds of the students it needs for a full freshman class next school year, a shortfall that could cost the public liberal arts school $3.5 million in lost tuition.

Though the school's admissions department is trying to fill about 150 vacant spots, the president warned faculty and staff to prepare for budget cuts.

"All of the numbers on this campus are small numbers, so this has a large impact," said President Joseph R. Urgo, who since becoming president in 2010 has revamped the school's admissions department. He recently replaced a longtime dean, adopted a generic application form and changed how the school doles out financial aid.

Urgo and other administrators at the Southern Maryland college said they are still trying to figure out what happened.

College admissions present a complex numbers game. Schools generally aim to increase their application numbers each year so they have a wide, rich pool — and so they can reject a greater number and become more selective. With students now applying to record numbers of colleges, it can be difficult to determine how many students who are accepted will actually enroll. Accepting too many students can lead to overcrowding in dorms and classrooms. And schools don't want to accept students who aren't fully qualified.

St. Mary's saw a 14 percent spike in the number of applications for next school year, likely because it began accepting the Common App, a generic application approved by hundreds of schools. St. Mary's accepted a "tremendous" group of students with high academic credentials, Urgo said, and also met goals for increasing racial diversity and the number of first-generation college students.

But not nearly enough of those who were accepted decided to enroll.

St. Mary's had hoped to recruit 470 freshmen for this fall, an increase from its usual class size of about 450. So far, about 360 have committed to attending, though that number likely will shrink over the summer, Urgo said. St. Mary's has received 32 applications since the deadline, and school officials are waiting to hear back from 25 students on the wait list.

School administrators have estimated the student shortage to be a $3.5 million hit, about 5 percent of the school's budget. Urgo said administrators have yet to determine what will be cut, but "we're trying our best so that no one loses their job."

He said that open positions likely won't be filled, and the school will look for efficiencies that don't affect the quality of academic instruction.

Charles "Chip" Jackson, the school's new vice president for business and finance, downplayed the impact. "It's only 5 percent of the budget," he said.

But news of the shortfall shocked many students who were still on campus last week. Dozens attended a Friday afternoon trustees meeting, filling the room and watching through open windows after receiving an unauthorized all-campus e-mail from then-student trustee Alex Walls.

"The administration has announced that they are looking into a wide variety of programmatic and personnel reductions," Walls wrote. "Translation, services could end and staff will be fired."

The admissions office hopes to fill those open spaces with late applicants, those who change their mind, and transfer students. The main message on the school's website on Monday proclaimed: "Applications are still being accepted — apply today!"

Urgo urged, like a salesman: "It's open season on second thoughts. ... We have seats open for the fall. It's a great education."

Patricia Goldsmith, St. Mary's vice president and dean of admissions and financial aid, noted that other liberal arts schools are seeing similar problems, though not to the same extent. "We are hoping to close the gap, but it's slow," Goldsmith said.

This isn't the first year that St. Mary's has had difficulty filling its freshman class, Urgo said. A majority of students who decide not to enroll usually do so for financial reasons and opt for one of the state's less-expensive public schools. St. Mary's is also seeing increased competition from private liberal arts schools that are able to discount their tuition. St. Mary's in-state tuition and fees were about $14,775 this school year.

"Our price, while it looks really good compared to privates, is a lot more than the publics," Urgo said. "Is this the perfect land to be in? Or is this no-man's land?"

St. Mary's trustees voted to freeze tuition this year after a burst of new state funding.