Normally for the Preliminary Examination, which takes place in the middle of May every year, advertisements are brought out towards the end of November or the beginning of December. Earlier the examination carried a total of 450 marks. In the optional subject, wherein there are 120 questions of 2.5 marks each, embraces the full marks of 300. The selection of candidates in prelims exam depends on the number of total vacancy in a particular year. For coming year (2011) in preliminary exam UPSC has proposed an aptitude test.

Generally the Main Examination commences from the middle of October to the first week of November. It is of 2000 marks. The division of marks is as follows:

The Main Examination consists of papers in Hindi and English. Though the marks obtained in these papers are not added to the cumulative score. Nevertheless, it is indispensably essential to get success in these papers because only the score of the pass marks in these papers will legitimatize the result of other papers. About 1500 to 1800 candidates are selected from the Main Examination. Candidates scoring 980 to 985 marks have a better chance of getting success in it.

The third step in the Civil Services Examination system is the interview, which evaluates the candidate's personality. The final result of the interview that carries full marks of 300 is added to the scores to the Main Examination. It is the combined result that determines the final rank. The possibility of success lies more with students who succeed in obtaining 1215 to 1220 marks in the end result.