High school students will be able to take Advanced Placement tests this spring at home or in school, on multiple possible dates, as the coronavirus pandemic continues to require unprecedented improvisation in academic routines.

But the exams will return to their usual length.

The College Board’s update on AP testing procedures, disclosed Thursday, seeks to bring the program at least a step toward normalcy even though basic operating conditions at schools across the country remain wildly uneven. Many classrooms are open, while others are closed or running with a mix of online and in-person teaching.

Last year, AP tests were cut to 45 minutes apiece and delivered online for the first time. The curriculum they covered was truncated in response to the sudden closure of schools in March, when the public health emergency slammed the nation.

Typically, the tests are two to three hours long. Their formats vary, but they generally pose free-response and multiple-choice questions. Students who score a three or higher on the five-point scale are often able to earn college credit or bypass introductory college classes in topics from biology to world history.

Last year, many students complained they could not submit test answers because of technical glitches, creating huge distress for those affected. But officials said the vast majority were able to complete the exams.

Under the College Board’s new plan, there will be three testing windows for each exam. The first, from May 3 to May 17, will allow students to take the tests at school with paper and pencil under traditional proctoring. The second, from May 18 to May 28, will allow testing in school or at home using computers. The third, from June 1 to June 11, is expected to be mostly at home but with some in-school sessions.

The at-home testing will use several measures to guard against cheating, officials said, including synchronous start times, plagiarism detection, computer-camera monitoring and restrictions on going back to previous questions to revise answers.

Trevor Packer, a senior vice president at the College Board who oversees the AP program, said the testing organization wants to offer students the option to challenge themselves with a full test if they desire.

“There are so many different situations that flexibility needs to be a paramount virtue this year,” Packer said. He said he hopes technical troubles will be minimized. “We absolutely have been able to learn from last spring’s experience,” Packer said.