A VERY rough estimate is that 3 drinks (a shot (1.25 oz) of whisky, 4 oz of wine, or 12 oz of beer) in a 160 lbs person will give you a BAC (blood alcohol content) of >0.1 (according to Spitz and Fisher in "The Medicolegal Investigation of Death", 3rd edition, p 564). Honestly, anything more...