1. What Is the U.S. National Chemistry Olympiad (USNCO)?
The USNCO is a multi-tiered national competition that challenges high school students across the United States to demonstrate their chemistry knowledge and problem-solving skills.
The journey begins at the Local Chemistry Olympiad, which is open to all high school students nationwide and organized through ACS Local Sections. Top performers from local competitions are nominated by their USNCO Coordinators to advance to the National Chemistry Olympiad Exam. From there, the top 20 students in the country are invited to attend an intensive two-week Study Camp. At the camp, students receive advanced training in theoretical and experimental chemistry. Based on their performance, four students are selected to represent the United States at the International Chemistry Olympiad (IChO), held in July 2026.
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2. Who Is Eligible and How to Participate?
Eligibility
To be eligible for the USNCO, students must meet the following requirements:
- Citizenship or residency: Participants must be U.S. citizens or legal permanent residents (green card holders) to take the National Exam. Non-citizen students may compete in the Local Exam but are ineligible for advancement to the National level.
- Grade level: Participants must be enrolled in grades 9–12 and graduate no earlier than May 1 of the competition year.
- Age limit: Students must be under 20 years old on July 1 of the competition year.
- Nomination limit: Each high school may nominate no more than two students per local section for the National Exam. For students in magnet programs or online schools, the “home school” is defined as the school from which they will receive their diploma.
How to Participate
Students begin their journey by participating in the Local Chemistry Olympiad, typically held in March. Below are the instructions to register:
- A parent or guardian must register the student with the American Chemical Society.
- Registration alone does not guarantee participation; coordinators need to confirm student eligibility and placement.
- Once approved, students will be notified by their USNCO Local Coordinator.
To find your local coordinator, please visit: https://www.usncolookup.acs.org/
3. USNCO Exam Format and Key Topics
Local Exam
- Duration: 110 minutes
- Format: 60 multiple-choice questions
- Content: Broad chemistry topics covering high school–level material
National Exam
The National Exam consists of three parts:
Part | Type | Duration | Description |
I | Multiple Choice | 90 min | 60 questions covering a wide range of chemistry concepts |
II | Free Response | 105 min | 8 written questions testing problem-solving and conceptual understanding |
III | Laboratory Practical | 90 min | 2 hands-on experiments involving data collection and analysis |
The multiple-choice sections of both the local and national exams generally include the following areas:
4. Competition Timeline
Student Registration Opens: October 6, 2025
Local Exam: February 27 – March 16, 2026
National Exam: April 10-19, 2026
Study Camp: June 2026
International Chemistry Olympiad (IChO): July 2026
Note: The schedule is subject to change. Updates will be communicated by USNCO Coordinators and posted on the official website.
5. How Difficult Is the USNCO?
The USNCO is considered one of the most challenging high school chemistry competitions in the world. While its scope is similar to AP Chemistry, the depth of questions, especially at the National level, extends far beyond the standard high school curricula.
Students are expected to master advanced problem-solving skills, apply conceptual understanding to novel scenarios, and perform hands-on laboratory experiments with accuracy and precision.
6. How to Qualify for the National Chemistry Olympiad
Only the top students from local competitions are nominated for the National Exam.
After the National Exam, approximately 50 students will receive High Honors, and the next 100 students will receive Honors awards. These distinctions are recognized with official certificates from the ACS and are published on the USNCO website.
From this group, the top 20 students are invited to the Study Camp, where the final US International Chemistry Olympiad Team will be selected.
7. How Can I Best Prepare for the USNCO?
Review Your Chemistry Knowledge
The USNCO covers material comparable to AP Chemistry, with additional topics in introductory organic and physical chemistry. Students can use AP Chemistry textbooks, question banks, and review materials for their foundational preparation before advancing to Olympiad-level resources. You can refer to this AP Chemistry study guide to start the preparation process.
Recommended Resources for USNCO Practice
The American Chemical Society (ACS) provides a variety of free online webinars and tutorials designed to help students prepare effectively for both the Local and National rounds of the USNCO. These sessions are led by experts and cover fundamental concepts, problem-solving strategies, and topic-specific guidance.
- Introduction to the USNCO for Students
- Preparing for the USNCO Local Section Exam
- Local Exam Tutorial: Atomic Structure and Periodicity
- USNCO National Exam: States of Matter
- Descriptive Chemistry and Laboratory Preparation
- USNCO – Local Exam Tutorial: Equilibrium
These resources provide a solid foundation for understanding the topics covered on the exam and help you identify the key areas of chemistry to focus your study efforts on. Once you’re familiar with the material, start practicing with questions and problems to strengthen your knowledge and skills before moving on to past exam papers.
Practice with Past Exams
One of the most effective ways to prepare for the USNCO is by working through past exam papers. Practicing with previous years’ questions allows you to experience the format, style, and level of difficulty of the actual exams. It also helps you identify recurring topics and question patterns that are emphasized in the competition.
After completing each practice exam, take time to review the solutions carefully. Analyze your mistakes to understand not only what went wrong but also why these errors happened. This reflective process strengthens your problem-solving skills and deepens your conceptual understanding.
You can access official USNCO past papers and resources through the American Chemical Society’s website:
The US National Chemistry Olympiad offers a rare opportunity for students to explore chemistry at an advanced level, challenge themselves intellectually, and connect with a nationwide community of young scientists. Whether your goal is to reach the International Chemistry Olympiad or simply to deepen your understanding of chemistry, the USNCO provides an enriching and rewarding experience that will strengthen both your academic and personal growth.
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8. How Do the USNCO and International Chemistry Olympiad (IChO) Competitions Differ?
The USNCO serves as the qualifying competition for the International Chemistry Olympiad, while the IChO is the final international competition in which national teams (4 students per country) compete against each other.
In terms of difficulty, the USNCO is designed to challenge students beyond a standard AP Chemistry curriculum, so it discusses broader and less specialized concepts than the IChO. The USNCO covers more advanced topics, while the IChO mainly tests creativity, deep understanding, and problem-solving. The IChO also promotes cultural exchange and a global scientific community among young chemists.
In terms of the exam format, the USNCO has multiple rounds to select the most outstanding and talented U.S. high school students. Students start in the local round, move on to the national round, and then participate in a two-week training camp to select 4 students for the national team. The IChO has 2 exams: one theoretical and one experimental (lab).
Prepare for the USNCO with Award-Winning Instructors
Chemistry is often considered one of the most challenging subjects for high school students, especially at the advanced level required for the USNCO. If you find yourself struggling with difficult problems from past exams or if you need structured guidance to prepare effectively, Aralia’s instructors are here to help.
Our award-winning teachers are experts in the field, with years of experience teaching Chemistry and AP Chemistry at some of the nation’s top academic institutions. They provide personalized instruction, targeted problem-solving strategies, and in-depth explanations to help students master complex concepts and perform confidently in the competition.
Chemistry
The course will survey various vital skills found in high school chemistry courses, including honors, Advanced Placement (AP), or International Baccalaureate (IB) chemistry. Rather than focusing on just the concepts students encounter during the first month of a chemistry course, we will skip around to the skills that truly distinguish the strongest students. An additional benefit of jumping from skill to skill is that students will gain a skill set that can be utilized at many different times throughout a future full-year chemistry class.
