The average undergraduate takes between five and six years to complete a degree, according to a new report by the National Student Clearinghouse Research Center. The average bachelor’s-degree candidate takes just over five years to graduate.

The findings of the report, which pulled data from 3,600 postsecondary institutions across the country, fly in the face of much of the popular perception of college-enrollment patterns, Doug Shapiro, executive director of the research center, said in a news release.

“These nontraditional behaviors have a dramatic effect on time to degree,” he said. “Each additional term or semester has the potential to increase the cost to the student, both through forgone earnings and additional tuition expenses.”

A quarter of bachelor’s earners took a full six years to finish, and women who began college after the age of 20 took the longest to earn their degrees, nearly nine years on average, according to the report. Attending multiple institutions is also a common trend, regardless of the time it takes a student to graduate, with more than half of all students at public four-year universities attending two or more institutions.

“Families and policy makers need to plan accordingly for this new reality,” Mr. Shapiro said.