An IQ test measures your *intelligence quotient*, a score that shows how your mental functioning compares with other people of your age. An IQ test won't directly tell you how intelligent you are, but it provides insight into how well you perform in quantitative reasoning, logic and memory. There are several different types of official IQ tests available, each of which use different approaches to exploring the ways people think.

Are Online Tests Valid?

It's easy to find a test that claims to give you your IQ score -- there are hundreds of tests online and available through social media that can provide you with an IQ score. However, these tests are usually unreliable. For example, your score may be calculated in relation to how quickly you finish the test, so you might get an extremely high score just by rushing through them. Mensa, a society for gifted and intelligent individuals, grants membership based on intelligence evaluation tests, including IQ tests, but accepts no online scores: the society offers an online test, but considers it only as a practice test. If you take an online IQ test, take your results with a grain of salt.

Where to Take Tests

In order to take a recognized clinical IQ test, your best bet is to find a private psychologist who can administer the test to you. This will allow you to obtain an official original copy of your results. Similar tests, such as the Wonderlic, are often offered by human resources departments looking to evaluate an individual's skills. Some private organizations also offer IQ tests -- Mensa, for instance, offers its own variant of the IQ test to see if individuals qualify for membership.

Different Types of IQ Tests

There are three different accredited IQ tests that are widely used. The Stanford-Binet test was developed in the early 20th century to evaluate the intelligence level of children, while the Wechsler scale was created mid-century to evaluate adolescent and adult intelligence. There are currently two different versions of the Binet test -- the Stanford Binet and Stanford Binet 5 -- and 14 variants on the Wechsler test that are accepted by Mensa for admission. The Cattell Culture Fair test is the main test used by Mensa's British wing. The Cattell test uses a slightly altered scoring scale from other IQ tests, and is designed to evaluate intelligence without cultural bias.

IQ Test Scoring

The three main types of IQ tests all use a scoring scale from 0 to 200. Test scores are calculated so that the average score for each test is 100 -- so a 100 IQ score designates average intelligence. The value of other scores is calculated in relation to 100. The Stanford-Binet and Wechsler tests use the same score scale: average intelligence is between 90 and 110; genius, or gifted, is above 140; and below 70 is considered mentally deficient. The Cattell test uses a wider scoring scale, so that scores between 90 and 140 are average, and genius level IQ is over 160.