Marler's Drinkometer

Tell the Drinkometer how much drink you've got, how strong it is and what it cost.

It will tell you how many units of alcohol are in it, and give you a score (units per pound; a "Marler").

This is all it can tell you; it cannot determine whether a drink will be nice, or whether it is a good idea to drink it. 

There are 568 ml in a pint; shots of spirits tend to be either 25 ml or 35 ml, or multiples thereof.