The Union Public Service Commission (UPSC) successfully conducted the UPSC Prelims Exam 2025 on 25th May 2025 across various exam centres in India. Thousands of aspirants appeared for this prestigious examination, marking the beginning of the multi-tiered Civil Services Examination process. The UPSC Prelims comprises two papers — General Studies Paper 1 (GS-I) and Civil Services Aptitude Test (CSAT) Paper 2 (GS-II). While GS Paper 1 is merit-based, CSAT is qualifying in nature, and candidates must secure at least 33% marks (66 out of 200) in this paper to have their GS Paper 1 evaluated.
With aspirants eagerly awaiting the official answer keys, APTI PLUS Academy, a reputed coaching institute, has released the unofficial UPSC Prelims Answer Key 2025 for reference. In this blog, we bring you detailed insights on the UPSC Prelims 2025 CSAT Answer Key, marking scheme, how to download the answer keys, and guidance to estimate your score.
Understanding the CSAT Paper: Format
The CSAT (General Studies Paper 2) is often underestimated due to its qualifying nature. However, its difficulty level has fluctuated in recent years, making it crucial for aspirants to take it seriously. Here’s a quick breakdown of the CSAT Paper 2025:
- Exam Time: 2:30 PM to 4:30 PM
- Total Questions: 80
- Total Marks: 200
- Minimum Qualifying Marks: 66 (33%)
- Question Type: Multiple Choice Questions (MCQs)
- Subjects Covered: Comprehension, Logical Reasoning, Analytical Ability, Basic Numeracy, Data Interpretation
UPSC CSAT Prelims Answer Key 2025
To help candidates self-evaluate, APTI PLUS Academy has published set-wise answer keys for the CSAT paper. While the official UPSC CSAT Answer Key 2025 will be released only after the final result, this unofficial key serves as a preliminary guide.
| Q. No | Ans | Q. No | Ans | Q. No | Ans | Q. No | Ans |
| 1 | C | 21 | A | 41 | B | 61 | B |
| 2 | D | 22 | D | 42 | A | 62 | C |
| 3 | D | 23 | A | 43 | C | 63 | C |
| 4 | D | 24 | D | 44 | B | 64 | C |
| 5 | C | 25 | C | 45 | D | 65 | C |
| 6 | A | 26 | D | 46 | C | 66 | B |
| 7 | C | 27 | B | 47 | C | 67 | A |
| 8 | B | 28 | D | 48 | D | 68 | D |
| 9 | D | 29 | D | 49 | A | 69 | D |
| 10 | A | 30 | C | 50 | C | 70 | D |
| 11 | D | 31 | D | 51 | B | 71 | B |
| 12 | A | 32 | A | 52 | C | 72 | D |
| 13 | D | 33 | B | 53 | D | 73 | D |
| 14 | A | 34 | B | 54 | D | 74 | D |
| 15 | C | 35 | B | 55 | C | 75 | D |
| 16 | C | 36 | B | 56 | A | 76 | C |
| 17 | B | 37 | C | 57 | D | 77 | C |
| 18 | C | 38 | B | 58 | B | 78 | A |
| 19 | D | 39 | C | 59 | B | 79 | A |
| 20 | C | 40 | B | 60 | C | 80 | C |
UPSC Prelims 2025 Marking Scheme: Know How to Calculate Your Score
To estimate your score using the answer key, follow the official UPSC marking scheme given below:
| Particulars | GS Paper 1 | CSAT Paper 2 |
| Correct Answer | +2 marks | +2.5 marks |
| Incorrect Answer | -0.66 marks | -0.83 marks |
| Unanswered Question | 0 marks | 0 marks |
| Total Questions | 100 | 80 |
| Total Marks | 200 | 200 |
Steps to Download UPSC Prelims Answer Key 2025 (Official)
Once the recruitment process is complete, the official UPSC Prelims Answer Key 2025 will be available at upsc.gov.in. Here’s how you can download it:
- Visit the official UPSC website – upsc.gov.in
- Click on the “Examinations” tab on the homepage.
- Select “Answer Keys” from the dropdown.
- Locate and click on “UPSC Prelims Answer Key 2025”.
- Download the PDF for GS Paper 1 and CSAT Paper 2 for your set.
Tips to Improve Your CSAT Score
Even though CSAT is qualifying in nature, its complexity has increased over the years. Here are some tips:
- Practice mock tests regularly to improve speed and accuracy.
- Focus on comprehension – UPSC often includes long passages.
- Strengthen basic numeracy and data interpretation.
- Analyze previous years’ papers to understand question patterns.
- Take CSAT as seriously as GS Paper 1 to avoid disqualification.