[DanBC]

To find the units in a drink you multiply the ABV by the serving size in litres.

One 200 ml glass of wine at 13% ABV would be 2.6 units.

One 330ml bottle of beer at 5% ABV is 1.65 units.

Most people struggle to estimate how many units of alcohol they drink. The "one unit == one drink" thing comes from when units were introduced, when a glass of wine would be 125 ml and it would only be 8%. Those days are long gone.

[magduf]

Maybe we should go back to those days. When I drink wine at home, I haven't measured it, but I'm quite sure I don't drink more than 125 mL at a time as I can easily get more than 6 glasses out of a standard 750mL bottle.