Answer:
A lot of factors come into play when answering this question. Among the many things that can effect your BAC, your gender, weight, and whether you have eaten recently can play the most obvious roles. Women are generally more susceptible to the effects of alcohol.
As I said earlier, there are many things that come into play when determining BAC. But to help estimate, go to this link ( http://en.wikipedia.org/wiki/Blood_alcohol_content#Effects_at_different_levels ) and scroll down to the third chart labeled as "Approximate Blood Alcohol Percentage US".