They make them especially easy online so you'll feel good about being smart. Those really aren't serious IQ tests, If you want to really know your numbers, you need to go to one of those exam centers and take the test.
However, recent researches in the past decade or so, really doubt how much those tests prove anyway - they refer to intelligent as a very narrow thing, when in fact it's much more complicated then the people who wrote the test originally perceive.