Overview
The Korean Olympiad in Informatics (KOI) is South Korea's national programming contest for school students. It has three divisions (elementary, middle and high school) and two rounds each year. High scorers in the middle and high school divisions can be invited to train for the International Olympiad in Informatics (IOI).
Who can enter
Students enrolled in elementary, middle or high school, including those on leave. Elementary and middle school contestants compete in regional or national categories; high school students are ranked in an overall division and a general high school division.
Levels or stages
Round 1
Held online on 10 May 2026. It has two sessions, of 80 minutes and 100 minutes. In 2026 there were six problems across the divisions. Awards run from gold to encouragement medals by percentile, with gold for the top 1.5%. Bronze or higher qualifies a student for Round 2.
Round 2
Practical programming, held online on 18 July 2026 from 12:30 to 18:00. Each division has four problems worth 100 points each, with partial credit. Allowed languages are C11, C++20, PyPy3 and Java 21. The fee is 80,000 won, and disadvantaged applicants can request a refund.
Marking and results
In Round 2, each division awards one Grand Prize, then Gold for the top 1 to 4%, Silver 4 to 12.5%, Bronze 12.5 to 37.5% and Encouragement 37.5 to 75%.
Important dates
For 2026, Round 2 registration ran from 26 June to 12 July.
After the competition
High-performing middle and high school winners in Round 2 go on to IOI training for 2026.
Preparation tips
Practise algorithm problems in C++ or Python under time limits, and use past KOI problems posted on the site.
Who can take Round 2?
Only Round 1 winners at bronze level or higher, in the matching division and category.