Money Bird

Ok.. I see the 2% rule brought up time and time again. How exactly do you calculate what is 2% of whats in your margin account? I'm using metatrader, and you buy by the lot it doesn't seem to tell me what exactly 2% of that would be. How would I be able to calculate what 10 pips up or down from my current position in a currency would be from my total margin? This may be a very stupid and obvious question, but I seriously don't get that.

I've been trading in a demo account for about two weeks now, doing good for the most part some trades have closed themselves I've noticed I'm guessing for going too far down my margin coutn didn't cover it. That again, I don't know how it knew to automatically close my account. But still stands the first question, how do i calculate this stupid 10% in relation to buying lots?