IMSO 2026 exam dates
Each row links to the organiser's original notice.
- Oct04International RoundInternational
Sunday, 04 Oct 2026 - 05 Oct 2026
Source: 23rd IMSO 2026Updated 07 Oct 2026
Past
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About IMSO
The International Mathematics and Science Olympiad (IMSO) is an annual olympiad in mathematics and science for primary school students. Contestants must be in primary school and no older than 13 before the first day of the olympiad, which in practice means students in Grade 5 and Grade 6. Each participating country sends one team for mathematics and one team for science, chosen through its own national selection.
IMSO past papers are a good way for upper primary students to get used to problems that go beyond the school textbook and are written entirely in English. This guide explains the IMSO levels, the two subjects, how the rounds work, the IMSO exam format and how to prepare with past papers.
Overview
IMSO was started in 2003 by the Ministry of National Education of Indonesia, under the name ASEAN Mathematics and Science Olympiad (AMSO). It later opened to countries outside Southeast Asia and became the International Mathematics and Science Olympiad. In 2011 the organizers decided to hold the event outside Indonesia for the first time, and since then the host country has rotated. The olympiad is run with an IMSO Executive Committee, and the 23rd IMSO takes place in Indonesia in 2026.
Recent hosts, according to the IMSO information page:
| Year | Host |
|---|---|
| 2017 | Singapore |
| 2018 | Zhuji, Zhejiang, China |
| 2019 | Hanoi, Vietnam |
| 2020-2023 | Online |
| 2024 | Wenzhou, Zhejiang, China |
| 2025 | Alor Setar, Kedah, Malaysia |
| 2026 | Indonesia |
Teams come from Asia, Africa, Europe and the Americas. Recent editions have included countries such as Indonesia, China, India, Malaysia, the Philippines, Thailand, Singapore, Vietnam, South Africa, Bulgaria and the United States.
IMSO levels and grades
| Level | Grades | Notes |
|---|---|---|
| Primary | Grade 5-6 | Primary school students, not older than 13 before the first day of the olympiad |
There is only one level. IMSO has no kindergarten or lower primary paper and no secondary school paper. The same level applies to both subjects.
Subjects
IMSO is one olympiad with two subjects. A student competes in one of them, and each country's mathematics team and science team are ranked separately.
- Mathematics. Three parts: Short Answer, Essay and Exploration. Short Answer questions only need the final answer. Essay questions require a written solution. Exploration problems are longer, multi-step investigations.
- Science. Two theory papers (Theory I and Theory II) and an Experiment. The theory papers combine multiple-choice and open-ended questions; the experiment is a practical task done with real equipment.
Standard teams have 6 students per subject plus a tutor. Former hosts and members of the IMSO Executive Committee may send twice as many.
Rounds
| Round | Who takes it | Notes |
|---|---|---|
| National Selection Round 1 | Eligible students who register | Run by each country; format set locally |
| National Selection Round 2 | Top scorers from Round 1 | Used in some countries only, such as Vietnam |
| International Round | The national teams | The IMSO olympiad itself, held in the host country |
The only round shared by every country is the International Round. Selection rounds belong to each country, and their papers are written by the national organizer, not by the IMSO committee. In Vietnam, for example, the IEG Foundation has held an online first round in English followed by an on-paper second round for the top 20 students in each subject, and then chose 12 students per subject.
IMSO exam format and scoring
- Language: all problems are in English. Students may bring a printed English to native language dictionary.
- Mathematics: Short Answer, Essay and Exploration papers. Answers in the Essay and Exploration parts are marked on the reasoning, not only the final number.
- Science: Theory I, Theory II and an Experiment. The theory papers mix multiple-choice and open-ended questions.
- Awards: about two thirds of contestants receive gold, silver or bronze medals in the ratio 1:2:3. There are also trophies for the overall champion, the best exploration score and the best theory score.
The official guidelines do not publish a fixed number of questions or a fixed time for each paper, so these can change from year to year. Check the information pack for the current edition before planning your timing.
When is IMSO held
IMSO takes place once a year in the host country, and in recent years it has been held around October. National selection usually happens a few months earlier, often in late summer. Registration is handled by the IMSO organizer in each country, usually through schools, so contact your national organizer to find out the selection dates and age cut-off for the coming year.
How to prepare with IMSO past papers
- Practise in English from the start. Problems are only given in English. Reading the question correctly is part of the challenge, especially for science vocabulary.
- Split your practice by part. Short Answer questions reward speed and accuracy. Essay questions reward clear written steps. Treat them as two different skills and practise both.
- Write out full solutions for Essay and Exploration. A correct number with no explanation can lose marks. After each paper, rewrite one solution as neatly as you would in the real contest.
- For science, do not skip the experiment. Online practice only covers the theory papers. Practise reading tables and graphs, controlling variables and explaining results in your own words, at home or at school.
- Use national selection papers too. If your country publishes its own selection papers, they are the closest match to the first hurdle you will face.
On Edupiad you can work through the IMSO papers we have, with a timer and automatic marking, then review every question afterwards. Papers that need a written solution or a lab task cannot be fully marked online, so use them to check your final answers and then compare your working with a teacher.
Frequently asked questions
What grade is IMSO for?
IMSO is for primary school students who are no older than 13 before the first day of the olympiad. In most countries that means Grade 5 and Grade 6.
Does IMSO have a secondary school level?
No. IMSO has a single primary level. Students who have moved on to secondary school usually look at other olympiads instead.
Can a student enter both mathematics and science?
Each country picks separate teams for the two subjects. In many national selections, such as Vietnam's, a student registers for only one subject.
Is IMSO hard?
Yes, it is aimed at strong students. Many problems go well beyond the Grade 5-6 curriculum, and the Essay and Exploration parts require clear written reasoning in English.