Overview
The National Science Olympiad starts with an examination held at numerous schools across the country and culminates with the international Olympiads at different corners of the world. The national level examinations are designed to assess conceptual understanding, logical reasoning, laboratory skills, and above all, the ability to apply problem-solving skills to novel situations, both theoretical and experimental. Training is included from the third stage of the programme and the first two stages do not necessarily require any specialised coaching outside the regular school system.
Official website: https://olympiads.hbcse.tifr.res.in/
- Stage 1: National Standard Examination (NSE)
- Stage 2: Indian National Olympiads (INOs)
- Stage 3: Orientation-cum-Selection Camps (OCSCs)
- Stage 4: Pre-Departure Camp
- Stage 5: International Olympiads
Important Dates 2026
Syllabus
Syllabus for NSEP, NSEC, NSEB, NSEA:
syllabus-for-nse-ino-2022-2023.pdf
Syllabus for INOP, INOC, INOB, INOA:
https://olympiads.hbcse.tifr.res.in/how-to-prepare/syllabus/#uagb-tabs__tab5
Official Updates Feed
ELIGIBILITY FOR NSE
A student needs to satisfy all the criteria listed below in order to appear for
the NSE in Science.
- Must be eligible to hold an Indian passport.
- Date of birth between 1 July 2007 and 30 June 2012, both days inclusive.
- Must be residing and studying in India since 30 November 2024 or earlier. Must be studying in an Indian school system since 30 November 2024 or earlier.
- Must not have completed (or scheduled to complete) class 12 board examination earlier than 30 November 2026.
- Must not have commenced (or planning to commence) studies in a university or equivalent institution by 1 June, 2027.
- Must not be appearing in NSEJS 2026.
ENROLMENT FOR NSE
Enrolment at student’s own school/college: A student can enrol for NSE
at his/her own institution if it is a registered NSE centre (see below for
registration of NSE centres). The principal would be the contact person for
this purpose.
Direct Enrolment: If a student’s own institution is not a registered NSE
centre, it is still possible to participate in NSE by enrolling directly on the
IAPT website: www.iapt.org.in.
Enrolment fees: Rs. 300/- per student per subject.
Enrolment dates: 21 August – 14 September, 2025 (check IAPT website)
ELIGIBILITY FOR INO
The aim of the first stage examination is to have a wide reach, to progressively
increase this reach and to attain nationwide representation for Stage II without
overly compromising on merit. Hence the selection for the Stage II
examinations, i.e., Indian National Olympiad Examinations (INOs) is based
on the following scheme.
- The student pool of each NSE (NSEA, NSEB, NSEC, NSEP) will be
divided into two groups:
▪ Group A: Students who are in Class XII as of November 30, 2025
▪ Group B: Students who are in Class XI or X as of November 30, 2025 - For Stage II (INO), a minimum target number of N students is set. This
number will be N = 200 for each of Biology, Chemistry, and Physics, and N = 250 for Astronomy for each of the groups A and B above. Thus, a total of minimum 400 students (for INBO/INChO/INPhO) or 500 students (for INAO) will be selected. - The selection of students for each group will be made according to the
clauses (a) to (e) below applied separately to each group. In particular, the Minimum Admissible Score (MAS) and the Merit Index (MI) will be
calculated separately for each group in each subject. - The syllabus and question papers of NSE 2025 and INO 2026 will be
identical for the two groups in each subject.- Minimum Admissible Score (MAS) Clause: To be eligible for the
Stage II (INO) exam leading to the International Olympiad, a
candidate must secure a score equal to or greater than a Minimum
Admissible Score (MAS). The MAS for a given subject will be 50%
of the average of the top ten scores in that subject rounded off to the nearest lower integer. This clause shall be a prerequisite for clauses (b) to (e) to be applied for any student.
Examples:- Suppose the average of the top ten scores in NSE in a subject is 92.3; then 50% of that is 46.15. The MAS will be set at 46.
- Suppose the average of the top ten scores in NSE in a subject is 93.5; then 50% of that is 46.75. In this case also the MAS will be set at 46.
- Merit Index (MI) Clause: There will be a high score called the Merit
Index (MI) associated with each subject in Olympiads. The MI in a
subject is defined as 80% of the average of the top ten scores in that subject, rounded off to the nearest lower integer. All students with a score equal to or greater than MI for the subject will automatically qualify for INO in that subject.
Example: Suppose the average of the top ten scores in a certain subject is 92.3, then 80% of that is 73.84. The MI in that subject will be set at 73. All candidates with a score equal to or above 73 in that subject will automatically qualify for INO. - Proportional Representation Clause: Students from all States and
UTs need to be encouraged to appear for the first stage examination, and a nationwide representation for the second stage is desirable. A quota for each State/UT, based on the erstwhile National Talent Search Examination (NTSE), will be applied for determining the number (with a minimum of 4) of students qualifying for INO in every subject from schools in that State or UT. This number will include those selected on the basis of the Merit Index (MI Clause (b) above). In the event of a tie at the last position in the list, all students with same marks at this position will qualify to appear for INO. The selected students must nevertheless satisfy the MAS Clause (a).
Examples:- Let the quota on the basis of the Proportional Representation
Clause (c) for a State S1 be 20. Suppose the number of students satisfying the Merit Index Clause (b) in a subject is 10. These 10 students will qualify for the INO exam in the given subject and an additional 10 students from the State S1 in the given subject will be selected merit-wise, provided they satisfy the MAS Clause (a). - Let the quota on the basis of the Proportional Representation
Clause (c) for a State S1 be 20. Suppose the number of students satisfying the Merit Index Clause (b) in a subject is 30. In this case, all 30 students will qualify for the INO exam in the given subject, and there will be no further selection from the State S1.
- Let the quota on the basis of the Proportional Representation
- Minimum Total Number Clause: In each subject, after all the above
criteria have been applied, it is possible that the target number of N students to be selected for INO is not reached (due to non-availability of enough number of students in some states who satisfy the MAS Clause (a)). In such an event, additional students will be selected purely merit-wise, provided MAS Clause (a) is satisfied, till the target number of N is reached. Other clauses will not apply for these students. In case of a tie at the last position, all students with the same marks at this position will qualify to appear for the INO Stage II examination. - Super-numerary Quota for Female Students Clause: A supernumerary quota for female students will be applied to ensure that a minimum of 15% of the total number of students selected for INO in each subject are female. The definition of a “female” student shall be as per self-identification of the student explicitly as “female” at the time of NSE registration. The implementation of this quota will be subject to the MAS Clause (a). For each subject, this clause will be applied only if the total number of female students is less than the target quota of 10% after all the above clauses (a) to (d) of qualification from NSE to INO, have been applied. In case this fraction of female students has already been reached through the application of clauses (a) to (d), then this quota will not be applied. If the fraction of female students is less than the target, then additional female students in order of merit, subject to qualification of MAS, but irrespective of region, will be added to the list of qualified students till the target fraction is reached (rounded upwards to the nearest integral number of students). In case there are not enough female students above MAS in a subject, the required number as per this clause may not be reached, and the shortfall shall not be transferable to any other category or clause.
Example: Suppose that after application of the clauses (a) to (d), the total number of selected students in a subject is 210. Now consider three scenarios:- The number of female students among these 210 is 35. In this case, the quota for female students will not be applied since the target quota of 15% of 210, i.e. 32, has already been reached.
- The number of female students among these 210 is 25. In this case, the quota needs to be applied since the target of 15% of 210, i.e. 32, has not been reached. Suppose there are 50 female students above MAS who have not yet been selected for INO. Then 8 female students, in order of merit, will be added to the INO list. This takes the total of students to 210+8 = 218 and the number of female students to 25+8 = 33, which is the closest integer greater than the target 15% of the total number, i.e. 32.7. Note that 8, and not 7 female students need to be added.
- The number of female students among these 210 is 25. Again, in this case, the quota needs to be applied since the target of 15% of 210, i.e. 32, has not been reached. However, suppose there are only 5 female students above MAS who have not yet been selected for INO. Then only these 5 students will be added to the INO list, even though the fraction of female students stays at 30/215 = 14%, which is less than the target of 15%. The MAS Clause (a) does not permit any further addition of female students.
- Previous International Representation Clause: Candidates who
have represented India in an International Olympiad (IOAA, IBO,
IChO, or IPhO) on a previous occasion need not appear for the first
stage NSE examination in the respective subject. Candidates who
have represented India in the Asian Physics Olympiad (APhO) and
the International Olympiad on Astronomy and Astrophysics
Olympiad Junior (IOAA-Jr) need not appear for the NSEP and NSEA examinations, respectively. Those candidates who thus qualify to skipthe NSEs may be allowed, on written request by email to nc_olympiad@hbcse.tifr.res.in, to directly appear for the Indian National Olympiad (INO) examination (in the respective subject only), provided they satisfy other eligibility criteria such as age, class of study, pre-college status, etc.
- Minimum Admissible Score (MAS) Clause: To be eligible for the
There will be no other criterion or provision for selection to the Indian
National Olympiad Examinations (INOs).
SELECTION PROCEDURE FOR OCSCs
For Biology, Chemistry and Physics, a target number of 20 students from each of Group A and Group B (see above) will be selected, according to order of merit in the respective INO. For Astronomy, a target number of 15 students from Group A and 35 students from Group B will be selected, according to respective order of merit in INAO. Thus, unless declared to be otherwise before the INO examinations, a total of 40 students for each of OCSCBiology, OCSC-Chemistry, and OCSC-Physics, and 50 students for OCSCAstronomy will be selected. In the event there is a tie at the last position in the merit list of the respective INO, all students with the same marks at the last position will qualify to be selected for the OCSC.
Selection of the team to represent India in any of the International Olympiads will NOT be based on the above groups, but will be done purely on the basis of a combined merit list of all students attending the OCSC in the respective subject.
The following procedure will be applied for selection of students for OCSCs. In a given year, a student can participate in the orientation/ training/ selection of only one subject including Mathematics (OCSC for the five science subjects, or International Mathematical Olympiad Training Camp (IMOTC)) according to a preference order decided by the student himself/herself. A student who qualifies in more than one subject (on the basis of his/her performance in INO or Indian National Mathematical Olympiad (INMO)) will be invited to the OCSC that is ranked highest in his/her preference list. The procedure is as follows:
- Before INO/INMO: A student who qualifies to appear in more than one subject in INO/INMO will be asked to arrange the subjects in order of preference of attending the OCSC/IMOTC (and therefore competing for selection in the international team). This preference will have to be indicated during the mandatory registration for INO. This will not affect in any way the evaluation of his/her INO/INMO performance in any subject.
- After INO/INMO: A target number of students will be invited to the OCSC camp of each subject. The students in each subject will be assigned a rank according to his/her performance in the respective INO/INMO.
If a student obtains qualifying marks in INO in multiple subjects, he/she will be included only in the OCSC/IMOTC for the subject which figures highest in his/her preference list among the subjects in which he/she has obtained qualifying marks. His/her name will not be considered for OCSC/IMOTC in the other subjects, and the next students in those subjects will be considered, till the target number of students is reached in each subject.
Irrespective of selection or participation in OCSC/IMOTC, the student will receive a Certificate of Merit in every subject in which his/her score is equal to or higher than the score of the last selected student in that subject.
The process of selection is illustrated below in an example with three possible cases. We consider the example of a Group A student, Amita, who has qualified for INO in Astronomy, Physics and Chemistry. Prior to INO, she declares her preference in the order: Physics, Chemistry, Astronomy. In this example, the target number of students in each subject in Group A is 20.
Case 1: Based on her INO performance, Amita is ranked 17th in Physics, 15th in Chemistry and 4 th in Astronomy. She will be selected in Physics OCSC and her name will not be included in Chemistry or Astronomy OCSCs. As a result, all the students ranked below her in Chemistry and Astronomy will gain one rank while being considered for OCSC selection. Amita will receive a certificate of merit in all three subjects.
Case 2: Amita is ranked 80th in Physics, 15th in Chemistry and 4th in Astronomy. She is unlikely to be selected for Physics OCSC because her rank is too low to be upgraded to higher than 20. She will now be selected in Chemistry OCSC, and not for Astronomy. She will receive a certificate of merit in Chemistry and Astronomy.
Case 3: Amita is ranked 22nd in Physics, 15th in Chemistry and 4th in Astronomy. She is initially not eligible for Physics, but has qualified for Chemistry and Astronomy. However, it so happens that two students ranked above her in Physics get selected in some other subject based on their preferences. Since their names are now removed from the Physics list, Amita’s rank goes up to 20, and she becomes eligible for Physics which is her first preference. Therefore, she gets selected in Physics, and not in Chemistry or Astronomy. She will receive a certificate of merit in all three subjects.
SCHEDULE OF OCSC
The OCSC dates will be announced on HBCSE website (olympiads.hbcse.tifr.res.in) by January 15, 2026.
To the extent possible, care is taken that the camp dates do not overlap with the national level competitive exams, (e.g. IIT-JEE or NEET). Students are advised to select Mumbai as their examination centre of any national level entrance examination that might be scheduled during the OCSC period.
The selection of the members of the Indian teams (IOAA, IBO, IChO and IPhO) holds provided they satisfy required criteria such as age limit, pre university status, medical fitness, parental/ guardian consent, etc. In addition, by the beginning of the OCSC they must hold an Indian passport that is valid till at least six months beyond the dates of the respective international Olympiad.
The decisions of the examination committees of the INOs and OCSCs in the various subjects regarding selection of international team, special merit awardees and other awardees will be treated as final.
Duration of Examination
Duration of Examination of Indian National Biology Olympiad (INBO):-
Duration: 2 hours
Maximum Marks: 300
Question numbers: 56
Duration of Examination of Indian National Chemistry Olympiad (INChO):-
Time: 3 hours
Maximum Marks: Total 109 marks
Question numbers: 5
Duration of Examination of Indian National Physics Olympiad (INPhO):-
Time: 3 hours
Maximum Marks: 75
Question numbers: 5
Duration of Examination of Indian National Astronomy Olympiad (INAO):-
Duration: 3 Hours
Maximum Marks: 100
Question numbers: 12
Mode of Examination
Offline
Choice of Medium of Question Papers
Marking Scheme
A) 48 multiple choice questions with one alternative correct. +3 marks credit for correct choice. –1 mark penalty for incorrect choice.
B) 12 multiple choice questions each of six marks with one or more than one
correct alternatives. To get credit, all the correct option(s) and no incorrect option (s) should be marked.