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UPSC Prelims 2026 Marks Calculator & Score Calculator

Calculate your estimated UPSC Prelims score based on your correct, incorrect, and skipped answers.

The UnlockIAS UPSC Prelims Marks Calculator (score calculator) applies the exact UPSC marking scheme — +2 marks per correct answer and −2/3 marks per incorrect answer (one-third negative marking) for GS Paper 1, with no penalty for skipped questions. CSAT Paper 2 uses +2.5 marks correct and −5/6 marks incorrect, with a 33% qualifying threshold (66.67 out of 200). Computations use the exact fractions rather than rounded decimals (0.67, 0.83) to avoid drift across 100 questions.

Total Questions: 100Correct: +2Incorrect: −2/3 (one-third)Max Marks: 200

How UPSC Prelims Scoring Works

GS Paper 1 Marking Scheme

  • Total Questions: 100
  • Each correct answer: +2 marks
  • Each incorrect answer: −2/3 marks (one-third of 2; decimal ≈ 0.6667)
  • Unanswered questions: 0 marks
  • Maximum marks: 200

CSAT Paper 2 Marking Scheme

  • Total Questions: 80
  • Each correct answer: +2.5 marks
  • Each incorrect answer: −5/6 marks (one-third of 2.5; decimal ≈ 0.8333)
  • Unanswered questions: 0 marks
  • Maximum marks: 200
  • Qualifying marks: 33% (66.67 marks)
  • CSAT is qualifying only — marks are not added to the merit ranking

Score Calculation Formula

Score = (Correct × Marks per Q) − (Incorrect × Marks per Q ÷ 3)

For GS: Score = (Correct × 2) − (Incorrect × 2/3)

For CSAT: Score = (Correct × 2.5) − (Incorrect × 5/6)

The fractions 2/3 and 5/6 are exact — using rounded decimals (0.67, 0.83) introduces a small drift that can accumulate across 100 questions.

Worked Example — GS Paper 1

Suppose you answered 75 correct, 20 incorrect, and skipped 5 questions out of 100.

Marks gained  = 75 × 2     = +150.00
Marks lost    = 20 × 2/3   =  −13.33  (exact: 40/3)
Skipped       = 5 × 0      =    0.00
Net Score   = 150 − 40/3 = 410/3 ≈ 136.67 / 200

Note: skipped questions carry zero penalty. Only incorrect answers attract the one-third negative marking deduction. With rounded decimals (0.67) you would get 136.60 instead of the exact 136.67 — a 0.07-mark drift that grows with more wrong answers.

Want a Question-by-Question Analysis?

Use our full evaluator to mark each question individually and get a detailed subject-wise breakdown with comparison against multiple institute answer keys.

Full Answer Evaluator →

Frequently Asked Questions

How is the UPSC Prelims score calculated?→
For GS Paper 1, each correct answer earns +2 marks and each incorrect answer deducts exactly 2/3 marks (one-third of 2). Unanswered questions carry no penalty. Total Score = (Correct × 2) − (Incorrect × 2/3). For CSAT Paper 2, correct answers earn +2.5 marks and incorrect answers deduct exactly 5/6 marks (one-third of 2.5).
What is the negative marking rule in UPSC Prelims?→
UPSC Prelims applies one-third negative marking. For a 2-mark question (GS Paper 1), exactly 2/3 marks are deducted per wrong answer. For a 2.5-mark question (CSAT), the deduction is exactly 5/6 marks. Unanswered questions are not penalised. Decimal approximations (0.67 for GS, 0.83 for CSAT) round the actual fractions and can drift over many questions.
Does the CSAT Paper 2 score count for the Prelims merit list?→
No. CSAT is qualifying only. Candidates must score at least 33% (66.67 out of 200) to qualify, but those marks are not added to the merit list. Prelims ranking is based on GS Paper 1 score alone.
What happens if I mark more than one option for a question?→
As per UPSC instructions, multiple answers for a single question are treated as a wrong response and attract the same one-third negative marking, even if one of the marked options happens to be correct.
Can I estimate my score before the official answer key is released?→
Yes. If you recall how many questions you answered confidently and how many you guessed, you can enter approximate counts to get an estimate. For a precise, question-by-question evaluation against multiple coaching institute keys, use the full Answer Evaluator on UnlockIAS.
How accurate is this calculator?→
The calculator applies the exact UPSC marking scheme. The accuracy of the estimate depends entirely on how accurately you remember your responses. For exact scoring, wait for the UPSC provisional answer key and use the full evaluator with your actual OMR responses.
What is the difference between marks calculator and score calculator?→
They are the same thing. "Marks calculator" and "score calculator" both refer to the tool that computes your UPSC Prelims marks/score by applying the official UPSC marking scheme (+2 per correct, −2/3 per incorrect for GS Paper 1). Our UPSC Prelims 2026 marks calculator uses exact fractions rather than rounded decimals for precision.