Prelims is a shorter, usually objective-type screening round that narrows down the candidate pool, while mains is a more detailed, often subjective round that decides the final ranking or selection.
Many large-scale competitive exams — especially government and civil services exams — use a multi-stage structure to manage a huge number of applicants efficiently.
Usually objective, multiple-choice format, testing broad general knowledge and reasoning. Its main purpose is to filter a very large applicant pool down to a manageable number who move forward — prelims scores often aren't counted toward the final ranking, only used for qualification.
Typically longer, more detailed, and includes subjective/written answers testing deeper subject knowledge, analysis, and writing ability. Mains scores (sometimes combined with a later interview stage) usually determine the final result and ranking.
Last reviewed: September 2026