But is this test really accurate? I have no idea. Here is a graph of results from this website over the last few years. The red "Empirical" line is the actual distribution, which shows a mode of 25 (perhaps implied a little bit higher), with a std of about 5 on the high side, and a low side that's not very normally distributed. (There is a second mode at zero, but this is just people opening the page and never submitting it, or just checking a few things at random.)
The (implied) claim from wherever this test originally came from is that the mean should be around 8.3, with a std of 8. This is shown as "Claimed" on the graph, which you can see is nowhere near the empirical results. However, the empirical results are selecting for people on the web taking an IQ test, which is surely a highly skewed population vs. randomly selected individuals from the general population...
Furthermore, no telling how many people took this two or more times claiming it was the first time, or who were using a browser that didn't handle the timer properly or otherwise defeated the timer...
In short, without running a study with randomly selected individuals from the general population (which I aint gonna do -- but contact me if you want to do it..), we have no way to know how this compares to other tests.
If you take this test for the first time and submit it within the alotted 20 minutes, and you happen to know your approximate IQ from other tests or sources, please send me an email with your score and IQ's as reported here, plus whatever you know from elsewhere. If I get enough feedback of this sort to say anything useful, I will update this page accordingly.