How to take the IQ test
- Press Start and do the practice puzzle: pick the parts that complete the missing square, then press Next.
- Solve the 20 test puzzles: pattern grids, where you build the missing square, and number series, where you type the next number. Each answer picks the next puzzle, harder after a right answer and easier after a wrong one. There’s no time limit.
- See your estimated IQ, how many adults in a room of 1,000 you’d outscore, and where you sit on the bell curve. See the answers goes through every puzzle.
How the IQ score is worked out
The test is adaptive. It starts with a puzzle pitched at an average adult, and each answer moves the next puzzle up or down. After 20 puzzles (12 grids and 8 number series) it has found the level where you solve about half of what it gives you, which says far more than counting right answers on a fixed list would.
The difficulty of every puzzle was measured in a study of 2,561 people applying to medical school in Germany. That tells the test exactly where you stand against them. To turn that into IQ, the test assumes that group averages an IQ of about 115, with a narrower spread than everyone (an SD of 12 rather than 15), since medical school selects on top grades. An older review of American medical students put them around 125, and applicants as a whole score lower than those admitted. If the assumption is off, every score moves by the same amount.
The number series were measured on a second group: 570 adults online, mostly in the US. To put both on one scale, the test assumes that group averages an IQ of about 103 and that its average member solved a little over half of the series it was given. Grids carry more weight in the score, since there are more of them and their difficulties were measured more precisely.
Where the puzzles come from
The puzzles are from the Open Matrices Item Bank, published by Marco Koch, Frank M. Spinath, Samuel Greiff and Nicolas Becker in the Journal of Intelligence in 2022 (Development and Validation of the Open Matrices Item Bank). They made 220 puzzles from six rules (adding, subtracting, keeping what differs, keeping what’s shared, rotating and completing a set) and released them free under the GNU General Public License v3. This test uses 218 of them: one the researchers dropped because it didn’t fit their model, and one that says almost nothing about ability, are left out.
The number series are of the eleven kinds studied by Bao Sheng Loe, Luning Sun, Filip Simonfy and Philipp Doebler (Evaluating an Automated Number Series Item Generator Using Linear Logistic Test Models, Journal of Intelligence, 2018), such as two series taking turns or a step that grows by one each time. The test makes a fresh series of each kind with new numbers every time, and uses the difficulty the study measured for that kind.
What the test measures
Puzzles like these, a grid with one square missing, are called figural matrices. Their best-known version is Raven’s Progressive Matrices. They measure fluid reasoning: spotting a rule you haven’t seen before and applying it. Number series test the same skill with numbers, and need nothing past adding and multiplying. Fluid reasoning is one of the abilities a full IQ test covers, and the one that leans least on language.
Tips for the test
- Look along the rows first, then down the columns. Most puzzles combine two or more rules, one per kind of part.
- Count the parts in each square. A row where the third square has more or fewer parts than the first two is usually adding or taking away.
- Check each kind of part on its own: the corners might follow one rule while the triangles follow another.
- An empty square can be the answer. If every part cancels out, press Next with nothing selected.
- For number series, write down the gaps between numbers. If the gaps make no sense, try every other number: two series may be taking turns.
- Don’t guess fast to finish sooner. A careless miss sends you to easier puzzles and costs points.