GreenLight BAC will provide you a real time calculation of your blood alcohol level using Widmark's formula. You can use both metric and imperial system.

It calculates your BAC in real time meaning that you can save multiple drinks close the app reopen it and see how much alcohol is left or just keep the app open and see how the BAC decreases with every second.

There is also an option to plan how much alcohol you can drink if you know when you have to drive.

NB! These calculations are statistical averages and may vary greatly from person to person based on the individual abilities of their bodies.