What is IQ?
IQ (intelligence quotient) is a standardised score describing how well a person reasons, spots structure and manipulates information compared with a large reference population of the same age. It is not a count of correct answers: raw performance on an intelligence test is converted onto a scale with a mean of 100 and a standard deviation of 15, so an IQ score of 115 sits one standard deviation above average.
Because the score is relative, an IQ number only means something alongside the test that produced it, the reference sample used to norm it, and the confidence interval around it. A responsible online IQ test always reports all three.
What does an intelligence test measure?
An intelligence test measures reasoning processes rather than learned knowledge. Modern cognitive assessment batteries sample several distinct abilities and pool them into a general score, because no single item type captures reasoning on its own.
- Logical reasoning — drawing valid conclusions from rules, sequences and conditionals.
- Pattern recognition — detecting hidden structure in visual and numeric series.
- Spatial reasoning — mentally rotating, folding and comparing shapes.
- Numerical ability — reasoning about quantity, proportion and rate.
- Working memory — holding and manipulating several items at once while solving.
What IQ does not measure
IQ says nothing about character, creativity, motivation, emotional skill or worth. It is a narrow measure of reasoning efficiency under time pressure, and it is influenced by sleep, stress, practice and testing conditions.
Treat any IQ score — including one from the Testora IQ test — as a screening indicator that helps you choose study and training strategies, never as a verdict about potential.
How is an IQ score calculated?
Each answer is weighted by the calibrated difficulty of the item, weighted responses are pooled into domain scores, and those domain scores are combined and mapped onto the 100-mean, 15-standard-deviation scale using the normative sample. The result is reported with a percentile so you can see the proportion of the reference group scoring below you.
Why confidence intervals matter
No cognitive assessment measures without error. The Testora IQ test reports a 90% confidence interval of roughly ±4 points, which means a reported 120 is best read as "very likely between 116 and 124".
Why a free IQ test can still be rigorous
Cost is unrelated to psychometric quality. What matters is item calibration, sample size and honest reporting — which is why the Testora IQ score and percentile are free and only the extended report is paid.