NSO 2027 exam dates
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About NSO
The National Science Olympiad (NSO) is a school science competition run by the Science Olympiad Foundation (SOF) in New Delhi, India, for students in Grade 1-12. From the 2026-2027 season SOF has renamed it the SOF International Science Olympiad (ISO), so newer materials use the name ISO while NSO past papers from earlier seasons carry the old name. Students sit a one-hour multiple-choice paper written for their own grade at a school registered with SOF.
This page explains the NSO levels and grades, the two rounds, the NSO exam format and marking scheme, and how to prepare with NSO past papers. Everything here applies to both names: NSO and the new SOF ISO are the same competition.
Overview
SOF runs a family of school olympiads, including contests in mathematics, English, computer science and general knowledge, and the science olympiad is one of its best known. The exam is the same paper for every participating school in a given grade. According to SOF, its olympiads are held in about 72 countries, mainly through schools that follow Indian curricula or have registered with SOF directly.
Why the name changed. SOF announced that from the 2026-2027 session the National Science Olympiad becomes the International Science Olympiad, to reflect participation from many countries rather than India alone. On Edupiad the competition keeps the short name NSO, because almost all existing past papers use it.
A common confusion. SOF's ISO is a school-based contest open to every student at a registered school. It is not the same as the international science olympiads for national teams, such as the International Junior Science Olympiad (IJSO) or the International Biology Olympiad. In the same way, SOF's maths contest IMO is different from the International Mathematical Olympiad.
NSO levels and grades
Each grade has its own paper. Grades 1 and 2 take only the first round.
| Level | Grade | Notes |
|---|---|---|
| Grade 1 | Grade 1 | Level 1 only |
| Grade 2 | Grade 2 | Level 1 only |
| Grade 3 | Grade 3 | Level 1 and Level 2 |
| Grade 4 | Grade 4 | Level 1 and Level 2 |
| Grade 5 | Grade 5 | Level 1 and Level 2 |
| Grade 6 | Grade 6 | Level 1 and Level 2 |
| Grade 7 | Grade 7 | Level 1 and Level 2 |
| Grade 8 | Grade 8 | Level 1 and Level 2 |
| Grade 9 | Grade 9 | Level 1 and Level 2 |
| Grade 10 | Grade 10 | Level 1 and Level 2 |
| Grade 11 | Grade 11 | Separate sections for Physics, Chemistry, and Mathematics or Biology |
| Grade 12 | Grade 12 | Separate sections for Physics, Chemistry, and Mathematics or Biology |
Rounds
- Level 1. Taken at the student's own school, on paper, in 60 minutes. SOF offers several exam dates in each season and the school chooses one.
- Level 2. Open only to students in Grade 3-12. SOF states that the class-wise top 5% of Level 1 participants are selected. Level 2 is a second written paper, not a trip abroad.
Results are published as school, zonal and international ranks, and awards are given at each of these levels.
NSO exam format and scoring
All questions are multiple choice. The Level 1 pattern published by SOF is:
| Grade | Sections | Questions | Total marks |
|---|---|---|---|
| Grade 1-4 | Logical Reasoning (5 x 1 mark), Science (25 x 1 mark), Achievers Section (5 x 2 marks) | 35 | 40 |
| Grade 5-10 | Logical Reasoning (10 x 1 mark), Science (35 x 1 mark), Achievers Section (5 x 3 marks) | 50 | 60 |
| Grade 11-12 | Physics and Chemistry (25 x 1 mark), Mathematics or Biology (20 x 1 mark), Achievers Section (5 x 3 marks) | 50 | 60 |
The Level 2 pattern drops the reasoning section. For Grade 3-4 it has 30 science questions plus 5 Achievers questions (40 marks), and for Grade 5-10 it has 45 science questions plus 5 Achievers questions (60 marks).
The Achievers Section contains higher-order questions and is worth two or three marks per question, so it carries a large share of the total. The marking scheme SOF publishes lists marks for correct answers only and does not mention a penalty for wrong answers.
When is it held
Level 1 is usually held between October and December, spread over several dates so that schools can pick one. Level 2 follows later in the same school year. Registration normally goes through a school that has registered with SOF, and exact dates change every season, so check the SOF website or ask your school.
How to prepare with past papers
- Check the syllabus for your grade. SOF publishes a class-wise syllabus. Students outside India should compare it with their own curriculum, because some topics may be taught in a different grade.
- Do not neglect Logical Reasoning. In Grade 1-10 it is worth 5 or 10 marks and covers patterns, series and spatial puzzles that are easy to improve with practice.
- Give the Achievers Section real time. Five questions there are worth 10 or 15 marks. Practise the multi-step application questions that appear in this section of past papers.
- Keep a steady pace. For Grade 5-12 there are 50 questions in 60 minutes, a little over one minute each. Timed practice shows which questions to skip and come back to.
- Answer every question. Since the published scheme shows no deduction for wrong answers, leaving a question blank only gives up a possible mark.
On Edupiad you can practise NSO past papers online with a timer, automatic marking and a question-by-question review afterwards. Coverage depends on which grades and years have been added, and not every question has a worked solution.
Frequently asked questions
Is NSO the same as the SOF International Science Olympiad (ISO)?
Yes. SOF renamed the National Science Olympiad to International Science Olympiad from the 2026-2027 season. Papers from earlier seasons carry the NSO name and are good practice for the renamed contest.
Which grades can take NSO?
Students in Grade 1-12 at a school registered with SOF. Each grade has its own paper. Level 2 is only for Grade 3-12.
Does NSO have negative marking?
The marking scheme published by SOF gives marks per correct answer for each section and does not mention any deduction for wrong answers.
How do you qualify for NSO Level 2?
According to SOF, roughly the top 5% of Level 1 participants in each class are selected. Grade 1 and Grade 2 have no Level 2.
Is SOF ISO the same as the International Science Olympiads for national teams?
No. SOF's contest is open to all students at registered schools. Olympiads such as IJSO or the International Biology Olympiad accept only small national teams chosen by each country.