I found this website through a FB pal and HAD to share it.
It's a simple little test - you just check off the words you know and it estimates your total English vocabulary based on how far you get.
Here's the link: http://testyourvocab.com/
It doesn't matter if English is your second language - the site gives the averages for both first and second language speakers. Have a go! And why not share your results below...I'm guessing that we book lovers have better than average vocabularies because we're exposed to so many more words.
My Score: 27,800 (pretty much average)