If you look at the chart explaining scores in the FAQ at IQTest.com (How well did I do? What does my score mean?) you'll see how the scores are distributed and how your score compares with scores of others.
IQ tests are designed so that the average score will be 100. The highest score you can achieve on our test is 156. A score of 99 would be almost exactly average.

Our test was designed for native English speakers. If you do not speak English very well, your score will be lower than it would be if you took a test in your native language.

If you are under the age of 16, you'll get a more valid score on a test designed for children your age. Age is not factored into the scoring of our test, but it is an important factor in tests for those under 16. Adult IQ scores usually remain constant over a lifetime.

Common sense would tell us that if a child scores well on an adult test, then his IQ score would probably be even higher on a test designed for children his age. But we have done the research only on adults, so we can't say for sure that our test produces valid scores for those under 16.