Inspired by [thread=106547]this thread[/thread] and the discussion therein, I had a quick look for some online vocabulary estimators. Here are three tests, just for comparison: 1. Test your vocabulary 2. Estimate the size of your vocabulary 3. Test your vocab Test 1 (C) is the one used in the previous thread. It's manual and you calculate your own score. Tests 2 and 3 are more automated. Results vary wildly from test to test! According to test 1 (version C of that test), my vocabulary is about 17000 words or so, which is good but not brilliant by any means. According to test 3, my vocabulary is over double that - 35,200 words - which puts me in the (approximately) 85th percentile. Pretty good, huh? And as for test 2, it says I understand 97834 words, can infer the meanings of another 7932 and recognise having seen another 6610. That would appear to make me a super-genius, but compared to other takers of that test, apparently I'm only in the 60th percentile - barely above average. What to make of this? I suspect these tests are just not very accurate. The most "scientific" of the three seems to be test 3, which admits to an error margin of plus-or-minus 10%. If that's the case, then my vocabulary could be anything from 31680 words to 38720 words. Either way, I'd say that's probably too high. If you want an ego boost, or just want to do these for fun, feel free to post your results here. But let's not take any of these tests too seriously. If you're going to do just one of the tests, I recommend test 3, but I strongly suspect its results are too high.