One 440ml can of Guinness stout contains 1.8 units of alcohol. The ABV of canned Guinness is 4.1%. Each 100ml of canned Guinness contains 0.41 units of alcohol.
The UK Chief Medical Officers advise that it is not safe to drink more than 14 units a week on a regular basis (source).
7.8 x 440ml cans of Guinness contains 14 units of alcohol.
|Units of Alcohol||1.8|
|Units (4 Decimal Places)||1.8040|
|Units per 100ml||0.41|
Source: Open Units
Licence: Creative Commons Attribution 4.0 International License