UPSC Prelims Guide 2027 — GS Paper I, CSAT & Negative Marking

Quick summary · Stage 1 screening

One-day objective screen: GS Paper I (100 Qs · 200 marks) sets the cut-off; CSAT (80 Qs · 200) is qualifying at 33% (~66.67). Both papers use one-third negative marking. Prelims marks do not enter final merit (2,025).

Total marks

400

GS-I 200 + CSAT 200

GS-I merit

100 Qs

Cut-off on this paper only

CSAT bar

66.67

33% of 200 · qualifying

Penalty

1/3rd

−0.66 GS · −0.83 CSAT

Screening

~2.5%

~13k of ~5.5L to Mains

Prelims negative-marking score simulator

Live · 1/3rd penalty

Model attempt scenarios for GS Paper I and CSAT with official-style marking.

Questions attempted85 / 100

Correct answers68

Correct

+2.00 × 68

Wrong

−0.67 × 17

Blank

0 × 15

Estimated net score

124.67 / 200

Accuracy 80% · Score 62.3% of paper

Comfortable vs recent Gen cut-offs

Formula: Net = (Correct × 2.00) − (Wrong × 0.667). Illustrative only — confirm marking in the official notification.

Exam scheme

Two-paper Sunday architecture

Parameter	GS Paper I	CSAT
Total questions	100	80
Total marks	200	200
Duration	2 hrs · 9:30–11:30 AM	2 hrs · 2:30–4:30 PM
Marks per correct	+2.00	+2.50
Negative penalty (1/3rd)	−0.66	−0.83
Unattempted	0 (no penalty)	0 (no penalty)
Merit status	Cut-off on GS-I	Qualifying ≥ 66

Paper I · Merit for cut-off

General Studies (GS I)

200 marks · 100 MCQs · 2 hours · AM shift

Practice topic MCQs in Shelf →

Your GS-I net score decides the Prelims cut-off. Penalty −0.66 per wrong answer (1/3rd).

Current Events

National and international affairs — politics, economy, summits, schemes, geopolitics, and science breakthroughs.

History of India & National Movement

Ancient, Medieval, and Modern India with emphasis on socio-religious reforms and the freedom struggle (1857–1947).

Indian & World Geography

Physical, social, and economic geography; drainage, monsoon, resources, and industrial locations.

Indian Polity & Governance

Constitution, political system, Panchayati Raj, public policy, rights issues, and statutory bodies.

Economic & Social Development

Sustainable development, poverty, inclusion, demography, fiscal/monetary policy, inflation, and banking.

Environment, Ecology & Climate

Protected areas, IUCN species, Ramsar sites, UNFCCC, carbon markets, and pollution.

General Science

Space tech, defence systems, biotechnology, AI, nanotechnology, and everyday physics/chemistry.

Paper II · Strictly qualifying

CSAT (Aptitude Test)

200 marks · 80 MCQs · 2 hours · PM shift · pass ≥ 66

Practice CSAT-style sets →

Marks are NOT added to the Prelims cut-off. Penalty −0.83 per wrong answer. Decision-making items typically have no negative marking.

Reading Comprehension

Passages on environment, philosophy, technology, and economy with inference and assumption questions.

Interpersonal Skills

Communication and contextual logical understanding.

Logical Reasoning & Analytical Ability

Syllogisms, blood relations, seating, directions, family trees, and critical puzzles.

Decision Making & Problem Solving

Situational administrative choices (often no negative marks).

General Mental Ability

Coding-decoding, series, analogies, and visual pattern reasoning.

Basic Numeracy (Class X)

Number systems, percentages, ratios, averages, TSD, work-time, permutations, probability.

Data Interpretation (Class X)

Tables, charts, graphs, pie diagrams, and data sufficiency.

10-year weightage

GS-I subject frequency (approx.)

Environment + Economy + Polity often hold ~49 questions (~98 marks) — enough alone to clear recent general cut-offs when accuracy is high.

Domain	10-yr avg	2024	2023	2022	2021	2020	Avg marks
Environment, Ecology & Climate	18	18	19	17	18	19	36
Indian Economy & Budget / Survey	16	15	14	18	14	15	32
Indian Polity & Constitution	15	16	15	11	18	17	30
History (Modern, Ancient & Art)	14	14	13	16	20	19	28
Geography (Physical, India & Maps)	13	14	16	13	10	10	26
Science & Technology	12	13	14	14	11	10	24
Current Affairs & Global Treaties	12	10	9	11	9	10	24

Attempt math

1/3rd penalty & elimination EV

Scenario	P(correct)	Expected (GS-I)	Call
2 options eliminated (50–50)	50%	+0.67 / Q (GS-I)	Usually attempt
1 option eliminated (1 of 3)	~33%	~0 (break-even)	Attempt if attempt count is low
Blind guess (1 of 4)	25%	Negative drift	Skip

Pair-count questions

Treat each statement as true/false on its own — do not start from the option labels.
If two pairs are locked true, you only need to decide the third to choose “only two” vs “all three”.
Partial elimination that worked on older “1 and 2 only” formats is weaker here — accuracy per pair matters.

Cut-off archive

Category-wise Prelims GS-I (recent)

Plan mocks for ~95+ GS-I and ~80+ CSAT so a volatile paper year still leaves margin (2024 Gen cut-off 87.98; 2023 dipped to 75.41).

Year	Gen	EWS	OBC	SC	ST
2024	87.98	85.92	87.28	79.03	74.23
2023	75.41	68.02	74.75	59.25	47.82
2022	88.22	82.83	87.54	74.08	69.35
2021	87.54	80.14	84.85	75.41	70.71
2020	92.51	77.55	89.12	74.84	68.71
2019	98	90	95.34	82	77.34
2018	98	—	96.66	84	83.34
2017	105.34	—	102.66	88.66	88.66
2016	116	—	110.66	99.34	96
2015	107.34	—	106	94	91.34

Full archive & safe-score studio in the cut-off hub.

FAQs

Prelims questions

What is the exact Prelims pattern?

Two MCQ papers same day: GS Paper I — 100 Qs, 200 marks, 2 hrs (9:30–11:30); CSAT — 80 Qs, 200 marks, 2 hrs (2:30–4:30). GS-I sets the cut-off; CSAT needs ≥ 33% (66.67).

Are Prelims marks in the final merit?

No. Prelims only screens for Mains. Final rank is from Mains (1,750) + Interview (275) = 2,025.

How does negative marking work?

One-third of the question’s marks. GS-I: +2 / −0.66. CSAT: +2.5 / −0.83. Unattempted is zero.

What clears CSAT?

At least 66.67/200. About 27 correct with zero negatives clears the bar; keep a buffer for wrong attempts (many aim 45–55 attempts at high accuracy).

Why do strong GS scores still fail Prelims?

CSAT is mandatory. Lengthy RC, number systems, and multi-step reasoning have raised difficulty — failing 66.67 voids a high GS-I score.

What are pair-count questions?

Options like “only one pair / only two pairs / all three”. Validate each statement independently, then count true pairs — classic partial elimination is harder.

How many GS-I questions should I attempt?

Recent safe bands often sit around 82–92 attempts with roughly 72–78% accuracy, but calibrate to your mock accuracy and the year’s paper.

Practise Prelims inside Shelf

File sources by topic, generate MCQs, ask Tutor beside the PDF, and schedule revision.

Open Quiz Prelims PYQs Cut-offs