How many words in your vocabulary?

Hi, what do you think, is there any reliable method of measuring your own active vocabulary? I mean, do you have any idea how many words you use on a daily basis? I know that the English language contains about 250.000 words and there is no way one person could ever know all of them let alone use them. So the question is how many words do you use when you communicate in English? Also, how many words do you think you know when you communicate in your mother tongue?