There are no genuine IQ tests on the Internet. The companies who develop real tests of intelligence for use by psychologists and psychometricians spend millions of dollars preparing and norming them. They do not make them available to the general public at all, let alone publish them on the Internet. Basic starter kits for professionals cost over $1000 and go up from there.
Some people like to put together collections of interesting or challenging problems and puzzles, label them IQ tests and publish them on line. It's a free Internet (mostly), so they can do that, but no one who has legitimate reason to be interested in a person's IQ will take them seriously. Even Mensa ignores them (and, in the USA at least, Mensa no longer tells applicants their scores on application exams -- only whether they qualified or not).
It's best to think of such web sites as puzzles and games, suitable for amusement only. If a psychologist or organization really wants to know your IQ, they'll arrange to test you themselves or look at prior evidence from school or military tests. They will not look at your scores on some internet game, no matter what it calls itself.
If you want to take a real IQ test, contact the Student Counseling Center at your local college or university. They often have psychologists or psychometricians on staff who can administer a test or refer you to someone who can. Sorry, it won't be free.