The following shows an example for 1 standard glass (175ml) of 11% ABV wine.
a) Calculate the UK units
strength (ABV) x volume (ml) / 1000 = UK units (NHS calculating units)
11 x 175 / 1000 = 1.925 units
b) Calculate the grams of alcohol
Assume that 1 UK unit = 8g of alcohol (Drinkaware alcohol facts)
1.925 x 8 = 15.4 g