The point of this website is to host a wide variety of tests that feature items commonly found on professional intelligence ("IQ") tests. The tests on this website will always be completely free to take, and it will always be completely free to view one's score on any test on this website. Additionally, the answers to every item on a test can be viewed after completing the test, along with explanations.
While there are many websites that purport to offer free IQ tests, I was unsatisfied with them for a variety of reasons.
Some of these websites only show one's score if one makes a payment. The tests are not free, according to my understanding of the phrase "free IQ test".
Some of these websites do not provide the explanations of the correct answers for the items on the tests they offer, and some do not even provide the correct answers. Professional intelligence tests (those designed by psychometricians) are carefully guarded from the public in all aspects, because they are used as diagnostic instruments by psychologists. Online IQ tests need not be so guarded.
Some of these websites have badly designed items or entire tests. Some items have questionable or outright incorrect answer choices keyed as the correct answer. Some tests are advertised as measuring IQ in general or as measuring general intelligence, but have a limited or oddly chosen variety of item types. Some tests feature types of items that do not appear on any professional intelligence test.
None of these websites aims to offer a truly comprehensive collection of tests that mimic the item types found on professional intelligence tests.
This website aims to be what these other websites are not: a comprehensive collection of completely free online IQ tests that are all well-designed and fully explained.