The role of CSAT in Prelims
Paper II, the Civil Services Aptitude Test (CSAT), has 80 questions carrying 200 marks and lasts two hours. It is a qualifying paper: you must score at least 33%, which is 66 marks, for your Paper I marks to be considered for the Mains shortlist, and its marks are not used in ranking. Each question carries 2.5 marks and a wrong answer costs one-third of that, about 0.83 marks. The 2026 notice sets out the rule and the pattern is summarised in our UPSC exam pattern guide.
The danger with a qualifying paper is neglect. Candidates who are comfortable with numeracy and reasoning sometimes ignore CSAT for months, and a bad paper on the day can end the attempt regardless of how well Paper I went. Candidates who are not comfortable with it sometimes spend too many hours on it. The right answer is a steady, modest routine that creates a safe margin.
What CSAT covers
| Area | What it involves | Share of effort |
|---|---|---|
| Reading comprehension | Passages with inference, main idea and implication questions | Largest block; the most predictable marks |
| Logical reasoning and analytical ability | Syllogisms, arrangements, series, statements and conclusions | Moderate |
| Decision-making and problem-solving | Case-based and situational questions | Small |
| Basic numeracy and data interpretation | Percentages, ratios, speed, averages, tables and charts, at about Class X level | Moderate |
| Interpersonal skills and communication | Appears within comprehension and decision-making questions | Small |
How much do you need?
With 2.5 marks per correct answer, 27 correct answers with no wrong ones score 67.5, just above the qualifying line. Because each wrong answer costs about 0.83 marks, a candidate who answers 40 questions with 10 wrong scores 30 × 2.5 − 10 × 0.83 = 66.7, which barely qualifies. The safe aim is a margin of 25 to 35 marks, which means about 36 to 40 net correct answers in practice. If your mock scores are consistently at or above 100, you are comfortable; if they hover near 70, give CSAT more weekly time.
Worked examples by area
Arithmetic. A train 150 m long passes a pole in 10 seconds. What is its speed in km/h? Speed = 150 ÷ 10 = 15 m/s = 15 × 18 ÷ 5 = 54 km/h.
Percentage. A price rises from 80 to 92. What is the percentage increase? 12 ÷ 80 = 15%.
Logical reasoning. Statements: All teachers are graduates. Some graduates are writers. Conclusions: (I) Some teachers are writers. (II) Some writers are graduates. Only II follows. The writers who are graduates may or may not include teachers, so I does not necessarily follow. Draw the diagram to check.
Series. 2, 5, 10, 17, 26, ? The differences are 3, 5, 7, 9, so the next difference is 11 and the answer is 37.
Data interpretation. Sales in four quarters were 120, 150, 180 and 210 units. What is the average per quarter? The sum is 660 and the average is 165.
All of these can be solved by routine methods in under a minute, which is the point: CSAT does not reward cleverness so much as steady, error-free application of basic methods.
Reading comprehension: the safest marks
Comprehension passages account for a large share of the paper in most recent years, and passage questions are, in principle, the most predictable. The method is to read the passage for its argument, answer from the passage rather than from general knowledge, and prefer the option that is supported but not extreme. Practise a daily passage with a time limit, as described in a daily reading comprehension routine. Aim to be accurate on at least 75 to 80% of comprehension questions, since these are where most candidates can secure a margin.
Reasoning and numeracy: build routines
For reasoning, learn the families (syllogisms, blood relations, direction sense, arrangements) and a standard method for each: Venn diagrams for syllogisms, trees for blood relations, coordinates for directions. Our topic pages on syllogisms, blood relations, direction sense and number series provide drills. For numeracy, revise percentage, averages, ratio and time, speed and distance, and practise data interpretation.
Time plan for the 80 questions
| Stage | Time | What to do |
|---|---|---|
| Comprehension passages | About 45 minutes | Take these first; they are the most predictable marks |
| Reasoning | About 30 minutes | Take families you are strongest in first |
| Numeracy and data interpretation | About 35 minutes | Quick questions first; skip long calculations |
| Check | About 10 minutes | Verify answers on the sheet |
This is about 90 seconds per question on average. Adjust it from your own timed practice and fix your order before the last month.
Negative marking in CSAT
A correct answer earns 2.5 marks and a wrong one costs about 0.83, so the break-even accuracy is again 25%. With the qualifying line the main concern, the cost of a wrong answer is higher than usual: each one costs you the equivalent of a third of a correct answer, and might be the difference on the day. Tag your answers as sure, eliminated or guess, as in the GS paper, and keep your policy conservative unless your mock results show that guesses pay. See our negative marking guide.
A weekly routine
- Two short sets (30 minutes each): one comprehension, one reasoning or numeracy, timed.
- One full paper every fortnight: 80 questions in two hours, with penalty applied, in the same time slot you expect.
- Weekly review: classify errors and update your error log.
If you are already scoring above 100, reduce to a full paper every three weeks to keep skills warm. If you are scoring below 85, add a third set a week and look at your error types.
Analysing your CSAT result
| Pattern | Probable cause | Action |
|---|---|---|
| Comprehension accuracy below 70% | Out-of-passage choices or slow reading | Daily passage practice; find the supporting line |
| Reasoning errors in one family | Method not mastered | Topic drills; use diagrams |
| Numeracy errors with right method | Arithmetic slips | Calculation drills; check the final step |
| Running out of time | Long numeracy questions early | Take comprehension first; skip long calculations |
| Guessed answers losing marks | Guessing without elimination | Compute net marks by tag; stop pure guesses |
Common mistakes in CSAT preparation
- Ignoring CSAT until the last month.
- Practising untimed, which hides the pace problem.
- Skipping comprehension, the safest block.
- Over-investing: spending more time than needed once the margin is secure.
- Guessing in a paper where one bad day matters.
Related pages
See the UPSC hub, the UPSC mock test strategy and the GS Paper I page. For a worked review, read how to use mock tests for UPSC. The CSAT tests published by institutes appear below.
Note: the figures above reflect the 2026 notice and published summaries; confirm the pattern and the qualifying mark for your cycle in the UPSC notice.