Bihar board class 10th main exam happens in February but if any student fails in one or two subjects then the board gives another chance and that is called the supply exam or compartment exam and this exam happens after six months which means around July or August but Bihar board mostly takes this supply exam in May like in 2025 the supply exam was held from 2 May to 7 May and for that the form was filled in April and the last date to fill the form was 16 April so the students who fail have to fill the supply form from their school and then they get the admit card and they give the exam in May and the practical exams are also held in April like on 29 and 30 April so if you fail in any subject then do not worry you get another chance to pass and you should fill the form on time and study again and if you pass the supply exam then you will get your marksheet and you can take admission in class 11 so the six month exam means this supply exam which comes after main exam and gives one more chance to students to pass and continue their studies.