UPSC Prelims vs Mains: What's the Difference and How to Prepare
Many UPSC beginners get confused about Prelims and Mains. What's the difference? Should you study differently for each? This guide explains everything in simple words.
Quick Overview
Think of UPSC as a three-stage race:
- Prelims = Qualifying round (MCQ based)
- Mains = Main competition (Written answers)
- Interview = Final selection (Personality test)
You must clear each stage to move to the next. Let's understand Prelims and Mains in detail.
What is UPSC Prelims?
Prelims is the first exam. It tests your general knowledge through multiple choice questions (MCQs).
Prelims Structure
| Paper | Questions | Marks | Time |
|---|
| GS Paper 1 | 100 MCQs | 200 | 2 hours |
| CSAT (Paper 2) | 80 MCQs | 200 | 2 hours |
Important: CSAT is only qualifying. You need just 33% (66 marks) to pass. Only GS Paper 1 marks count for cutoff.
What Prelims Tests
- Factual knowledge - Do you know the facts?
- Current affairs - Are you aware of recent events?
- Elimination skills - Can you remove wrong options?
- Speed - Can you manage time well?
Prelims Cutoff (Approximate)
- General: 90-100 marks
- OBC: 85-95 marks
- SC/ST: 75-85 marks
What is UPSC Mains?
Mains is the real competition. It tests your understanding and writing skills through descriptive answers.
Mains Structure
| Paper | Type | Marks |
|---|
| Essay | 2 essays | 250 |
| GS Paper 1 | History, Geography, Society | 250 |
| GS Paper 2 | Polity, Governance, IR | 250 |
| GS Paper 3 | Economy, Environment, Security | 250 |
| GS Paper 4 | Ethics | 250 |
| Optional Paper 1 | Your chosen subject | 250 |
| Optional Paper 2 | Your chosen subject | 250 |
| Language Papers | English + Regional | Qualifying |
Total Marks: 1750 (written) + 275 (interview) = 2025
What Mains Tests
- Deep understanding - Do you really understand the topic?
- Writing skills - Can you express ideas clearly?
- Analysis - Can you think from different angles?
- Opinion - What do you think about issues?
- Application - Can you apply knowledge to real problems?
Key Differences: Prelims vs Mains
1. Question Type
Prelims:
- Multiple choice (MCQ)
- One correct answer
- Negative marking (1/3rd)
- No partial marks
Mains:
- Descriptive answers
- Write in your own words
- No negative marking
- Partial marks possible
2. What They Test
Prelims:
- Breadth of knowledge (know a little about many topics)
- Facts and figures
- Current events
- Quick decision making
Mains:
- Depth of knowledge (know a lot about each topic)
- Understanding and analysis
- Multiple perspectives
- Clear expression
3. Study Approach
Prelims:
- Cover syllabus widely
- Focus on facts
- Practice MCQs daily
- Current affairs (1 year)
Mains:
- Go deep into topics
- Understand concepts
- Practice answer writing
- Form your own opinions
4. Preparation Time
Prelims:
- 4-6 months focused preparation
- Final 2 months: intense revision
Mains:
- 3-4 months after Prelims
- Answer writing practice daily
How to Prepare for Prelims
Step 1: Build Your Foundation (3-4 months)
Read NCERTs first. They give you the basic knowledge.
NCERT Books to Read:
- History: Class 6 to 12
- Geography: Class 6 to 12
- Polity: Class 11-12
- Economy: Class 11-12
- Science: Class 6 to 10
Step 2: Add Standard Books (2-3 months)
After NCERTs, read one standard book per subject:
- Polity: M. Laxmikanth
- Economy: Ramesh Singh
- Geography: G.C. Leong + NCERT
- History: Spectrum (Modern History)
- Environment: Shankar IAS
Step 3: Current Affairs (Ongoing)
- Read newspaper daily (30-45 minutes)
- Make short notes
- Focus on last 12 months before exam
- Link current events with static topics
Step 4: Practice MCQs (Daily)
- Solve 50-100 MCQs daily
- Analyze your mistakes
- Take full-length mock tests
- Learn elimination technique
How to Prepare for Mains
Step 1: Understand the Syllabus Deeply
Read each topic from multiple sources:
- Base: NCERTs and standard books
- Add: Government websites, PRS, PIB
- Current: Newspapers, magazines
- Opinions: Editorials, analysis
Step 2: Make Notes for Mains
Your Mains notes should have:
- Key points (for quick revision)
- Examples (real-world cases)
- Data (numbers, statistics)
- Different viewpoints (pros and cons)
- Your opinion (what you think)
Step 3: Practice Answer Writing
This is the most important part of Mains preparation.
How to practice:
- Write 2-3 answers daily
- Time yourself (7 minutes for 150 words)
- Get feedback if possible
- Improve based on mistakes
Answer writing tips:
- Start with introduction (2-3 lines)
- Use headings and bullet points
- Include examples and data
- End with conclusion/way forward
- Keep handwriting neat
Step 4: Choose Your Optional Wisely
Your optional subject carries 500 marks. Choose based on:
- Your interest
- Overlap with GS
- Scoring potential
- Availability of resources
- Syllabus size
Popular optionals: Psychology, Sociology, Geography, PSIR, Public Administration
Common Mistakes to Avoid
Prelims Mistakes
- Studying too deep - Prelims needs breadth, not depth
- Ignoring CSAT - Don't fail because of CSAT
- Less MCQ practice - Theory alone won't help
- Ignoring current affairs - 15-20% questions come from CA
- Not taking mocks - Practice under exam conditions
Mains Mistakes
- Not writing answers - Reading alone won't help
- One-sided views - Show multiple perspectives
- No structure - Use proper format
- Generic answers - Be specific with examples
- Bad handwriting - Examiner must be able to read
Smart Strategy: Prepare Together
Here's a secret: You can prepare for both together!
How It Works
Many topics overlap. When you study for Prelims, go slightly deeper for Mains.
Example - Fundamental Rights:
For Prelims: Know all 6 rights, important articles, key cases
For Mains: Same + analysis of how rights have evolved, recent debates, your opinion on restrictions
Time Division
If you have 12 months:
- Months 1-6: Foundation + Prelims focus
- Months 7-8: Prelims intensive
- After Prelims: Mains intensive (3-4 months)
Daily Schedule
| Time | Activity |
|---|
| Morning | Static subject reading |
| Afternoon | Current affairs + notes |
| Evening | MCQ practice (Prelims) |
| Night | Answer writing (Mains) |
Which is Harder: Prelims or Mains?
Both are hard in different ways:
Prelims is hard because:
- Competition is very high (10 lakh+ applicants)
- Cutoff can be unpredictable
- One silly mistake can cost you
- Negative marking pressure
Mains is hard because:
- You must write 26+ answers in 3 hours
- Depth of knowledge required
- Expression matters
- Consistency across 7 papers
Truth: Clear Prelims smartly, save energy for Mains. Mains decides your rank.
Final Tips
For Prelims
- Don't aim for perfection - Target 95-100 marks, not 150
- Attempt wisely - 75-80 questions with 70% accuracy
- Master elimination - Even partial knowledge helps
- Take 30+ full mocks - Build exam temperament
- Revise multiple times - Revision is key
For Mains
- Write daily - No shortcut to answer writing
- Use examples - Makes your answer stand out
- Be balanced - Show both sides of arguments
- Time management - Practice finishing on time
- Revise your notes - Not books, notes
For Both
- Stay consistent - Study daily, even if less
- Don't compare - Everyone's journey is different
- Stay healthy - Sleep well, exercise, eat right
- Stay motivated - Remember why you started
- Trust the process - Results will come
Conclusion
Prelims and Mains are two different challenges. Prelims tests your knowledge breadth, Mains tests your depth and expression.
Key takeaways:
- Prelims = MCQ, facts, speed
- Mains = Descriptive, analysis, writing
- Prepare smartly for both
- Practice is more important than reading
- Stay consistent and patient
Your UPSC journey is a marathon, not a sprint. Understand both stages, prepare accordingly, and you'll succeed.
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