There are three stages in the BPSC (Bihar Public Service Commission) exam:

1. Preliminary Examination:
The first stage of the BPSC exam is the Preliminary Examination. This exam is conducted to shortlist candidates for the next stage. It consists of two papers, both of which are objective type. The syllabus for the Preliminary Examination includes subjects like General Studies, Indian National Movement, Indian History, Geography, Polity, Economy, General Science, and Current Affairs. The duration of each paper is two hours, and each paper carries 150 marks.

2. Main Examination:
Candidates who qualify the Preliminary Examination move on to the Main Examination. This stage consists of a written examination followed by an interview. The Main Examination consists of six papers, all of which are descriptive in nature. The papers include subjects like General Hindi, General Studies, Optional Subject 1, Optional Subject 2, and two additional papers related to the Optional Subjects. Each paper carries 100 marks, and the duration of each paper is three hours.

3. Interview:
Candidates who clear the Main Examination are called for the interview stage. The interview is conducted to assess the candidate's personality, communication skills, and knowledge in their chosen subject. The interview carries 120 marks, and candidates are required to bring their original documents for verification. The final selection is based on the candidate's performance in the Main Examination and the interview.

In summary, the three stages of the BPSC exam are:
1. Preliminary Examination
- Objective type exam
- Consists of two papers
- Syllabus includes General Studies, Indian National Movement, Indian History, Geography, Polity, Economy, General Science, and Current Affairs
- Each paper carries 150 marks
- Duration of two hours for each paper

2. Main Examination
- Written examination followed by an interview
- Consists of six papers (General Hindi, General Studies, Optional Subject 1, Optional Subject 2, and two additional papers related to the Optional Subjects)
- All papers are descriptive in nature
- Each paper carries 100 marks
- Duration of three hours for each paper

3. Interview
- Conducted to assess the candidate's personality, communication skills, and knowledge in their chosen subject
- Carries 120 marks
- Candidates required to bring original documents for verification
- Final selection based on performance in the Main Examination and interview.