As per the latest branch change criteria at IIT BHU, the number of incoming students to a branch after a branch change should not surpass 10% of the current students in that branch. For instance, if the Mechanical branch has 87 students enrolled in the first year, then the number of students that can change their branch to Mechanical is 10% of 87 = 8.7. Then 8 students are eligible for branch change from Mechanical
The application for branch change is usually invited after the end of the first year.