Average IQ in South Korea: Why It Tops Online Tables but Not Adult Skills

The average IQ in South Korea is 100 on a Korean-normed test, as it is in every country. The 106.97 that tops online tables is the mean of 26,996 volunteers who took one website’s test in 2025, so it describes that audience. Korean 15-year-olds rank 5th in our PISA 2025 school ranking (maths 522), yet Korean adults rank 24th of 31 in the 2023 adult skills survey.

This guide explains the three numbers, why they disagree and what an OECD finding about older Koreans means. It also covers the figure people look up for North Korea.

What is the average IQ in South Korea?

It depends on the question. By definition, it is 100 on a test normed on Koreans. Four published numbers get quoted instead. They measure different people in different ways, and none is a national IQ test.

Why does South Korea top the online IQ table?

Its volunteers average 106.97, the highest of 137 countries, up 0.54 from 106.43 the year before. The sample is 26,996 people, well under one in a thousand of Korea’s 51 million residents. With an SD of 15 the standard error is 0.09 points, so the number is precise for the people who took the test. It is silent on who they are.

China is second at 106.48 and Japan third at 106.30. The gap to China is half a point, larger than the sampling error but too small to mean anything about nations. Our report on the 2026 online ranking shows the sample counts behind every score.

To put the sample in proportion, 26,996 takers are about 1 in 1,900 Korean residents. A year earlier, China led the table at 107.19, South Korea was second at 106.43 and Japan third at 106.40. Korea’s first place is a gain of 0.54 points for it and a loss of 0.71 for China, not a leap in a nation.

How do South Korean students score?

Very well. Korean 15-year-olds average 522.3 in maths, 500.6 in reading and 526.1 in science on PISA 2025, 5th in our school ranking. Japan is 4th at 521.9. The maths gap between Korea and Japan is 3 points with a standard error of 5.8, so the two are tied.

The trend is down. Since 2012, Korea has lost 31.5 points in maths, 35.2 in reading and 11.7 in science, taking maths from about 554 to 522. The maths loss is more than four times its standard error of 7.1. PISA is a school test, so the fall says nothing direct about IQ. Our post on PISA and IQ tests explains why.

The pattern is clear. Korean and Japanese students are close, but Japanese adults average 39 points higher. Our average IQ by country page, a smaller compilation of published studies, lists 102.35 for South Korea from 3,586 people in 4 studies.

Why do Korean adults rank 24th of 31 in the adult skills survey?

Because older Koreans score much lower than younger ones. In the OECD’s own words, “In literacy, adults aged 55-65 scored 55 points lower than 25-34 year-olds (OECD average: 30 points lower).” The OECD adds that the gap could reflect ageing effects and also differences in the quality and quantity of education and training across generations.

The OECD also notes that Korea saw the largest increase among participating countries in the share of 55-to-65-year-olds. It saw the largest increase in the share of tertiary-educated adults too. So a country can have top school scores and a lower adult average at the same time. Korean adults average 246.4 against 285.5 for Japan, which ranks 2nd.

Which countries sit near South Korea in the online table?

The top ten of the 2026 online table is a mix of large and tiny samples. Spain (11th) and Canada (13th) are also in the top 15.

New Zealand’s 102.35 rests on 1,184 people and Mongolia’s on 2,437, so small samples sit beside large ones in the same list. Only South Korea, China, Japan, Iran, Russia and Viet Nam have more than 10,000 takers.

What is the average IQ in North Korea?

No test data exist. Our average IQ by country page lists 103.76 for North Korea, marked as an estimate with no sample behind it. The 2026 online table does not include North Korea at all. Treat any figure for it as a guess, not a result.

Is South Korea smarter than Japan or China?

The tables cannot say. Online, Korea (106.97), China (106.48) and Japan (106.30) are within 0.7 points of each other, and the volunteers differ in every country. On PISA 2025 Japan is slightly ahead of Korea, but not by a margin that matters. In adult skills Japan leads by 39 points. A country does not have one IQ. It has skills that vary with age, schooling and the test used.

How should you read these numbers?

• Use 100 as the average on a Korean-normed test, and ignore national “IQ” headlines that skip the sample.
• Use PISA for 15-year-olds and the adult skills survey for adults, because both sample people at random.
• Check the age mix before comparing countries: Korea’s adult ranking reflects older generations.
• Read the online table as a picture of web visitors.

To see where your own score sits, take the IQ test and use the IQ percentile calculator. For other countries, see our posts on Germany and Canada, or the full average IQ by country table.

For a bigger comparison across 91 countries see our smartest countries in the world study. A South Korean claim of an extreme individual score is checked in our report on the Younghoon Kim 276 IQ claim.