Most free IQ tests online give everyone the same 20 or 30 questions and turn the number of right answers into a score nobody can check. Our IQ Test works differently. Its main mode is adaptive: every answer you give decides which puzzle comes next, and the score comes from a statistical model built on puzzles that researchers have already tested on thousands of people. This guide explains what happens behind the screen and how to read your result.
What "adaptive" means
An adaptive test (computerised adaptive testing, or CAT) behaves like a good examiner:
- It starts with a fairly easy puzzle.
- After each answer it re-estimates your ability.
- It then picks one of the puzzles that will tell it the most about someone at your current estimate — usually one you have roughly an even chance of solving.
- It stops as soon as the estimate is precise enough.
Get a puzzle right and the next one is harder; get one wrong and it gets easier. So everyone misses some puzzles — that is how the test homes in on your level, not a sign that you are doing badly.
Our test stops after at least 12 scored puzzles once the standard error drops to 0.3 (about ±5 IQ points), and never runs past 25 puzzles or 40 minutes. Two unscored practice puzzles come first.
Where the puzzles come from
The puzzles are from the Open Matrices Item Bank (OMIB), published by Koch, Spinath, Greiff and Becker in the Journal of Intelligence in 2022 and released under the GPL-3.0 licence. The researchers built 220 figural matrices from six construction rules and gave them to 2,572 applicants to medical schools. From those answers they estimated each puzzle's difficulty and how sharply it separates stronger from weaker reasoners (its discrimination). We use 217 of them.
That calibration is what makes adaptive scoring possible: the test knows in advance how hard each puzzle is.
You build the answer instead of choosing it
Each puzzle is a 3 × 3 grid with the bottom-right cell empty. Instead of picking from A–F, you tap pieces — corner triangles, diagonal lines, small bars, a centre square or circle, small triangles — to build the missing cell. It only counts if it matches exactly.
This "construction" format is how the bank was calibrated, and it removes a common shortcut: with multiple choice you can often eliminate options without understanding the rule. With 20 pieces to combine, guessing almost never works.
How the score is calculated
- Every answer updates an ability estimate (θ) using a two-parameter item response theory model, taking each puzzle's difficulty and discrimination into account.
- θ is measured against the calibration group. Because they were medical-school applicants — an above-average group — we assume their average equals IQ 110, so IQ = 110 + 15 × θ. We say this on the result page, because it is an assumption, not a measured norm.
- The 90% range shown under your score is the estimate ± 1.645 standard errors. If it says 112 (range 105–119), your true score on this kind of test is very likely somewhere in that band.
How to take the test
- Open the IQ Test and choose Full IQ test (adaptive).
- Do the two practice puzzles — they show the correct cell if you miss.
- For each scored puzzle, look along the rows, work out what changes from the first cell to the second to the third, and build the last cell.
- Confirm. Answers can't be changed afterwards, because the next puzzle depends on them.
- Read your score, range and percentile, then open Review puzzles to compare your cells with the correct ones.
Getting a fair result
- Take it when you are rested and won't be interrupted for half an hour.
- Don't use pen-and-paper notes or search for answers — the score is only meaningful if you solve the puzzles yourself.
- Don't rush, but don't spend five minutes on one puzzle either. Missing hard ones is expected.
- Retaking straight away usually raises the score a little because you have learned the format; the first attempt is the more honest one.
What the test can't tell you
It measures non-verbal (fluid) reasoning only. A full IQ assessment also covers vocabulary, working memory and processing speed, and is given in person by a psychologist with norms for your age and country. Treat the result as a good estimate of one important ability, not a diagnosis.
FAQ
Why did I get a different number of puzzles than my friend? The test stops when your score is precise enough. Scores near the middle settle quickly; very high or very low scores need more puzzles because the bank has fewer items at the extremes.
Is a wrong answer worse early or late in the test? Neither. The final estimate uses all your answers together, weighted by how hard and informative each puzzle was.
Is my answer data stored? No. The whole test runs in your browser; nothing is sent to a server.
Try it now
Start the free adaptive IQ test — about 20–30 minutes, no sign-up. Want a lighter warm-up first? The same page has a 30-question practice test with worked answers.