Working out exactly what is a standard drink is not always easy. One standard drink contains 10 grams of pure alcohol (the same as 12.5ml of pure alcohol). This amount of alcohol is found in (approximately): 285ml full-strength beer or cider 375ml mid-strength beer 425ml light-strength beer 100ml wine 30ml shot of spirits So, you must measure standard drinks by the amount of alcohol they contain, and not by the number of glasses that you consume. Check the label of any bottle, can or cask of alcohol for the number of standard drinks it contains. You can also use these calculators to work out how much you are drinking: Standard drinks calculator by DrinkWise