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UPSC Prelims pattern explained: GS Paper I, CSAT, and what decides who reaches Mains
UPSC Prelims has two objective papers of 200 marks each. CSAT (Paper II) only needs 33%. GS Paper I alone decides who reaches Mains. Neither paper counts in your final rank, which comes from Mains and the interview.
Many aspirants learn the Prelims pattern from a coaching page or a friend, and a few details get lost on the way. This guide sets out the pattern in UPSC's own words, from its notice for the Civil Services Examination 2024, and explains what each rule means for you.
The two papers
The Civil Services (Preliminary) Examination has two papers. Both are objective, with multiple-choice questions, and both carry 200 marks. Each paper is two hours long.
- General Studies Paper I: 200 marks. In the 2025 paper, this was 100 questions with four options each, so each question carries 2 marks.
- General Studies Paper II, called CSAT: 200 marks. It tests comprehension, reasoning, decision making, basic numeracy and data interpretation, at about Class X level for the maths.
You must sit both papers. The notice says plainly that a candidate who does not appear in both papers will be disqualified.
CSAT only needs 33%
Paper II is "a qualifying paper with minimum qualifying marks fixed at 33%". On 200 marks, that is 66 marks.
Its marks do not add to anything. A score of 66 and a score of 180 in CSAT have the same effect: you pass the gate. But a score of 65 ends your Prelims, however well you did in Paper I. The notice says the list for Mains is drawn on two conditions together: at least 33% in Paper II, and the qualifying total in Paper I.
So CSAT deserves a plan of its own. Some aspirants who are strong in GS take it lightly. But the 33% line applies to everyone, whatever their GS score.
GS Paper I decides who reaches Mains
Once you clear the 33% in CSAT, your Paper I score is the only thing that counts. UPSC sets a qualifying total in Paper I "as may be determined by the Commission". This is the Prelims cut-off. It is set each year and differs by category.
How many candidates qualify is fixed by the vacancies. The notice says the number admitted to Mains will be "about twelve to thirteen times" the number of vacancies that year.
This is why every mark in GS Paper I matters, and why the cut-off moves from year to year: it depends on how hard the paper was and how many vacancies there are, not on a fixed pass mark.
