There are charts and calculators online that estimate how many alcoholic beverages can be consumed before hitting the legal limit of .08 blood alcohol content. Unfortunately, it is only an estimate. It is not a perfect science, as there are many factors that impact the absorption of alcohol in the body.
These charts look at gender. Why is gender important? Men and women absorb alcohol differently in part because women tend to have a higher proportion of body fat than a man of the same weight. Men tend to have more muscle mass. Higher levels of muscle mass slow alcohol absorption, because some of the alcohol goes into the muscles.
The charts also factor in weight. Weight is not actually the important factor. It is body mass. Body mass, however, is not a commonly used measurement as it is expensive and time consuming. So, the closest measure available is weight, providing an estimated body mass. However, it is only a best guess. An overweight man who weighs 250 pounds will not be able to drink as much as a weight-lifter who weighs the same.
The amount of alcohol in each drink is obviously a factor in determining how many drinks one can consume before reaching the legal limit. A general rule of thumb is one can of beer = one glass of wine = one shot of liquor. Drinking a glass of hard liquor is a good deal more than a single serving.
Other factors involved in determining how many drinks it takes to hit the legal limit include length of time and food consumed. Someone who ‘chugs’ their alcoholic beverage will rapidly push the blood alcohol content up. Someone who drinks without food to slow down the absorption will also speed up the process. It is helpful to sip slowly, while eating and talking over a meal.