CIMO 2027 exam dates
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About CIMO
The Copernicus Mathematics Olympiad, often called CIMO in some countries, is an international mathematics competition run by Copernicus Olympiad, an organization founded in 2020 in Houston, Texas, USA. It is open to school students in five grade categories, from the early primary years up to Grade 12. Students first take an online Preliminary Round, and those who score at least 40% can register for an in-person Global Round.
"CIMO" is a local label used by some country partners, including the official representative in Vietnam; the organizer itself uses the name Copernicus Mathematics Olympiad. This guide explains the CIMO levels, the CIMO exam format and scoring, the rounds, and how to make good use of CIMO past papers.
Overview
According to its website, Copernicus Olympiad is a brand of Eve & Ant LLC, registered in Texas. It was created in 2020 by educators with international experience and is named after the astronomer Nicolaus Copernicus. Besides mathematics, the same organizer runs olympiads in natural science, physics, astronomy and entrepreneurship. Its natural science and physics and astronomy contests are known in some countries under the shared name CISO, which makes CISO the sister contest of CIMO.
The organizer reports participants from around 50 countries across Asia, Europe, Africa and the Americas. Students can register directly on the Copernicus Olympiad website or through an official country representative. Papers are offered in English, Spanish, Russian and French.
CIMO levels and grades
The Mathematics Olympiad is grouped into five categories, each covering two or three school grades.
| Level | Grades | Notes |
|---|---|---|
| Category 1 | Grade 2-4 | 2026-2027 official rules list Grades 3 and 4; some earlier seasons and partners also admitted Grade 2 |
| Category 2 | Grade 5-6 | |
| Category 3 | Grade 7-8 | |
| Category 4 | Grade 9-10 | |
| Category 5 | Grade 11-12 |
There is no Grade 1 category. Some partners, including the Vietnamese representative, write the categories in Roman numerals (Category I to Category V).
Rounds
- Preliminary Round. Every registered student takes an online qualifying exam, organized directly or with national representatives. In some countries it is called the national round. Students who only want to take this round can still earn medals and certificates from it.
- Global Round. Students who score at least 40% in the Preliminary Round are eligible and must complete a separate registration. The Global Round is held in person, and the venue is announced each season. Recent mathematics Global Rounds have taken place in New York and in Dubai.
The organizer also names an "Absolute Winner" in each category: the top scorer, with the younger student ranked first when scores are tied. Absolute winners are exempt from the Global Round registration fee, though travel and visa costs remain with the family.
CIMO exam format and scoring
The format has changed several times. The table shows the official rules for the 2026-2027 season.
| Item | Preliminary Round | Global Round |
|---|---|---|
| Questions | 20 multiple choice | 15 multiple choice + 5 open-ended |
| Time | 75 minutes | 75 minutes |
| Easy questions | 5 x 4 marks | 5 x 3 marks |
| Medium questions | 10 x 5 marks | 5 x 4 marks |
| Hard questions | 5 x 6 marks | 5 x 6 marks |
| Open-ended questions | None | 5 x 7 marks |
| Wrong answer | -1 mark | -1 mark on multiple choice, no penalty on open-ended |
| Total | 100 marks | 100 marks |
Earlier papers look different. The Vietnamese partner described the 2024 national round as 25 multiple-choice questions in 60 minutes, and another country partner listed 15 multiple-choice plus 5 open-ended questions in 90 minutes. When you practise with past papers, check which format the paper follows.
Preliminary Round medals use fixed score bands: 91-100% Gold, 75-90% Silver, 50-74% Bronze and 40-49% Honourable Mention. In the Global Round, medals are relative: Gold for the top 10%, Silver for the next 11-30%, Bronze for 31-60% and Honourable Mention for 61-75%.
When is CIMO held
The mathematics Preliminary Round is usually held online in the winter months, around December and January, with Global Rounds later in the following year. Dates and venues change every season and partners may run their own schedule, so confirm with the organizer or your country representative.
How to prepare with CIMO past papers
- Know the point value of each question. Harder questions are worth more, but every wrong answer costs one mark. Secure the easy and medium questions first, then spend the remaining time on the hard ones.
- Use the 40% target as a first goal. Reaching 40 out of 100 marks qualifies for the Global Round. Once you reach it regularly on past papers, aim for the medal bands.
- Practise open-ended answers. Global Round papers include five questions without answer choices. Practise writing a final numerical answer carefully, because there is no list to check against.
- Guess only with a reason. On multiple-choice questions, eliminate at least one option before guessing. Blind guessing on hard questions can cancel out marks you earned elsewhere.
- Match the format to the year. Since the number of questions and the time limit have changed, time yourself according to the format of the paper you are using.
On Edupiad you can take CIMO past papers online with a timer, have them marked automatically, and review each question after you submit. The years and solutions available vary by category.
Frequently asked questions
What is the difference between CIMO and the Copernicus Mathematics Olympiad?
They are the same contest. Copernicus Mathematics Olympiad is the official international name; CIMO is the label some country partners use.
What grades can take CIMO?
The current official rules cover Grades 3 to 12 in five categories. Some earlier seasons and partners opened Category 1 to Grade 2 as well. There is no Grade 1 level.
Does CIMO have negative marking?
Yes. In the 2026-2027 rules, each wrong multiple-choice answer loses 1 mark. Open-ended questions in the Global Round have no penalty.
How do I qualify for the CIMO Global Round?
Score at least 40% in the Preliminary Round, then complete the separate Global Round registration.
Is CIMO hard?
The paper mixes easy, medium and hard questions, and the hard ones go beyond the usual school syllabus. The qualifying mark for the Global Round is 40%, well below the 91% needed for a Preliminary Round gold medal, so the contest rewards both steady basics and strong problem solving.