UPSC Prelims answer key: the provisional key, objections, and the final key

On 24 May 2026, aspirants sat the Prelims. Three days later, on 27 May, UPSC put out a provisional answer key for GS Paper I and CSAT. That had never happened before. Until 2025, the only official key came out about a year after the exam: the 2025 key was published on 13 May 2026.

So there are now two keys for each Prelims. This post explains what each one is, how to check your score with it, and how the objection process works.

Why UPSC started publishing a provisional key

For years, aspirants had only coaching keys in the days after Prelims, and no way to question UPSC's answers before the result. A group of candidates went to the Supreme Court about it (Himanshu Kumar & Ors. v. Union of India).

In September 2025, UPSC filed an affidavit agreeing to publish a provisional key after the Prelims. The Supreme Court closed the case on 14 October 2025 on the basis of that affidavit. In March 2026, the government told the Rajya Sabha that this applies "from the Civil Services (Preliminary) Examination 2026 onwards", and to all of UPSC's objective-type exams.

The two keys

• The provisional key comes a few days after the exam. It is UPSC's answer before any objection is heard. Answers in it can still change.
• The final key comes after the final result of the whole examination, after the interview. UPSC's affidavit says the key that its experts finalise after the objections is the basis of the Prelims result. The public copy of that key comes later.

This explains a line that confused many aspirants in 2026. The Prelims result notice of 15 June 2026 says the answer keys go up only after the final result. It means the final key. The provisional key was already out by then.

How the objection window works

UPSC's 2026 notification sets the rule: objections are taken from the third day after the exam until 6 pm on the seventh day. For the 24 May 2026 exam, that was 27 May to 31 May, 6 pm.

• Where: only online, on UPSC's portal upsconline.nic.in, under "Representations on Question Paper". UPSC does not accept objections by email, post or hand.
• What to send: the question, the answer you think is right, a short explanation, and supporting documents from three authentic sources.
• What happens to weak objections: UPSC's affidavit says objections without such support are rejected "at the threshold".
• Who decides: teams of subject experts review every objection. UPSC does not reply to candidates one by one.

How to write an objection that gets read

UPSC does not publish a list of which sources count as authentic. A safe choice is the primary text: the Constitution or the Act itself, a ministry or government website, an NCERT book, or a report by a government body. A coaching note or a YouTube video proves only that someone else agrees with you.

Object only where you can show the key is wrong, not where you only feel the question was unfair. One question, one answer, three sources.

How to check your score with the provisional key

UPSC prints each Prelims paper in four booklet series, A, B, C and D. The questions are the same, but their order is shuffled. Check the series printed on your booklet first, then use the key for that series. If you use the wrong series, nearly every answer will look wrong.

Then count the marks for GS Paper I:

• +2 for every right answer
• −0.67 (one-third of 2) for every wrong answer
• 0 for every question you left blank

Only GS Paper I decides whether you reach Mains. CSAT has to be cleared at 33%, that is 66.67 out of 200. Our post on the Prelims pattern explains how the two papers work together.

Keep two things in mind:

1. Your score is an estimate. The experts can change an answer or drop a question after the objections.
2. Your score is not a result. The cut-off is known only after the final result. Our post on cut-offs year by year shows how much it moves.

How to read the final key

The final key gives one page for each booklet series. At the top, it says how many questions UPSC dropped. For 2024, the header reads: Total 100, Dropped 3, taken for Scoring 97. A dropped question is marked X in the answer column.

UPSC dropped questions from the final GS Paper I key in five of the last ten years: 2 in 2020, 1 each in 2021, 2022 and 2023, and 3 in 2024. It dropped none in 2016 to 2019 or in 2025. So in about half the years, the final key scored fewer than 100 questions.

What to expect in 2027

UPSC's calendar for 2027 puts the Prelims on 23 May 2027. If UPSC follows the 2026 rule, the objection window would run from 26 May to 6 pm on 30 May 2027. Check UPSC's own notice for the exact dates when it comes out. We will update this post then.

Why CollectorX uses only the final key

Every PYQ in CollectorX is checked against UPSC's final key, never the provisional key or a coaching key. That is why the 2026 paper is not in CollectorX yet: its final key will come only after the 2026 final result. When it does, we add the paper, and every answer you see is the one UPSC finally scored.