Countries with fewer than 100 test-takers were excluded from the ranking due to limited sample size and are shown in gray on the map above.
FAQ
Back to the country ranking or the interactive map.
What is the worldwide average IQ?
IQ tests are standardized so the overall average is 100 (with a standard deviation of 15). In this dataset, the global mean is 100.
Why are most countries’ averages below 100?
Short answer: weighting and representation.
In 2025, China alone accounted for about
17.02%
of the world’s population and posted a high average score (106.48) in this dataset. Because of its size, China has a meaningful impact on population-weighted averages and can offset many countries that come in below 100.
If you weight countries by population and their average scores, the global average still comes out to 100.
What is the official International IQ Test website?
international-iq-test.com is the original “International IQ Test” website and has been active since 2018.
You can check a site’s history using the Wayback Machine (archive.org).
This IQ test has been taken by more than 16 million people and has been calibrated using standard psychometric methods.
Why do average IQ scores differ across countries?
Differences across countries can reflect many factors. Researchers often discuss influences such as:
-
Health burden (including exposure to infectious diseases):
A 2010 study found that countries with higher infectious-disease burden often score lower on cognitive tests, potentially through impacts on development and schooling.
Africa is among the regions most affected by infectious diseases.
-
Nutrition and food security:
A 2024 study suggests that children with healthier dietary patterns tend to score higher on IQ measures. As a result, countries with healthier diets (and less food insecurity) may show higher average scores.
-
Learning opportunities and cognitive stimulation:
A 2022 study reported that regularly playing chess may improve children’s performance on IQ-related measures.
A classic 1962 study found that bilingual children performed better on certain intelligence tests than monolingual children. More broadly, cognitively stimulating activities practiced regularly within a culture can be associated with stronger reasoning performance.
-
Genetics (within-population influence):
A 2013 twin study reported that IQ heritability estimates often fall in the 50%–80% range, depending on age and population.
(Importantly, heritability describes variation within a population under specific conditions—it does not, by itself, explain differences between countries.)
Overall, countries with stronger health systems, better nutrition, and broader access to high-quality education and cognitively enriching environments tend to score higher on reasoning-based tests.
Some research also reports long-term increases in test performance over time (often called the
Flynn effect). A
2014 study
observed gains of about 2.31 IQ points per decade.
That said, IQ tests are standardized to center the distribution around a mean of 100. The International IQ Test’s scoring algorithm may be updated over time to keep the mean near 100 with a standard deviation of 15.
How often is the country ranking updated?
The ranking is updated once per year, on January 1, using the previous calendar year’s results.
How reliable is this ranking?
All scores in this ranking come from people who took the
International IQ Test on this website
between January 1, 2025 and December 31, 2025.
The test is inspired by the Raven’s Progressive Matrices format, a nonverbal reasoning measure designed to be more culture-fair than language-heavy tests.
The test produced a mean of 100 and a standard deviation of 15 over three consecutive years in this report, and reported an internal g-saturation of 0.943 over two consecutive years in this report.
In the country ranking, 84.8% of countries stayed within 2 points of their prior-year average.
Are all test results included in the ranking?
No. When compiling annual rankings, we use a screening process to remove likely repeat attempts, suspected bots, and responses flagged as suspicious (based on internal criteria).
Signals that may be used include (for example): IP address patterns, usernames, email addresses, and payment information.
The same screening criteria are applied to every country without exception.
Why do some small countries have more test-takers than larger countries?
Participation varies for many reasons, including:
- Local interest in IQ tests and related trends (including media coverage or events that drive traffic in specific regions).
- How search engines rank and surface the website by country and language.
As a result, the number of test-takers can vary substantially by country and by year.
Some countries have fewer than 1,000 test-takers—why include them?
Some countries may appear to have too few participants to be representative (those with fewer than 1,000 test-takers).
However, when comparing their averages year over year, 76.47% of these countries shifted by less than 2 points.
Their averages therefore do not appear to be meaningfully less stable than those of countries with larger samples.
Limitations of this ranking
Key limitations include:
- Internet access bias: All participants had internet access. In 2025, an estimated 74% of the world’s population had internet access, so coverage is not universal.
- What the test measures: Raven-style matrices focus on nonverbal reasoning and pattern recognition—they don’t capture every domain of intelligence.
- Online test constraints: Any online IQ test should be treated as informational, not diagnostic.