Wolfram Alpha is the place to go to do all kinds of calculations. You can even use it to estimate your blood alcohol level after you've put away a few drinks.
Note that this will only be an estimate since it ignores variations in metabolism, food intake, medication and so on. As always, we don't recommend you use this to judge whether you can drive -- it will never be accurate enough to judge whether you're within the legal limit. Don't drink and drive, no matter how well you may think you handle your liquor.
That said, it's an interesting little tool. Here's what you do:
- Go to Wolfram Alpha.
In the search box, input the following:
BAC 5 drinks, 3 hours, male, 80kg(change the number of drinks, the period of time you spent drinking and your weight).
- Click the = button or press Enter on your keyboard. The results will be displayed.
It will show you what your blood alcohol percentage is and even show you a graph of (roughly) how long it will take to get back down to zero. Again, it's not perfect -- and it shouldn't judge whether you're sober enough to drive -- but it is a cool function.