Alcohol

Once upon a time drinking in England was easy.
Beer, lager and cider were sold in pints or halves.
Wines sold at 6 glasses to a bottle.
Spirits 32 shots to the bottle.
There were 8 pints or 6 bottles to the gallon.

An English pint is twenty ounces giving a 160 ounce gallon.
An American pint is sixteen ounces, giving a 128 ounce gallon.

Then Metrication reared its head!

Pints stayed at the same volume but now 568 ml, although sometimes in third pint as a taster.
Shots change to 25 ml or 30 shots a standard bottle, with 35 ml, and 50 ml options.
Bottles changed from a standard 750 ml (3/4 litre) to 700, 750, or 1 litre. Plus the 3 litre box.
Wine glasses from 125 ml or now small, adding 175 ml standard with 250 ml large.

Now units of alcohol are easy one litre of 10% alcohol = 10 units, and 40% e.g. whisky 40 units or 1 unit per shot.

So two cans of lager at 500 ml = 1 litre and at 5% = 2.5 units per tin.

I common practise a 500 ml tin poured into a pint glass gives a pub pint!

Thus my conclusion is that one of the problems with modern day drinking is you are often given the same drink in vastly varying quantities.

Seezya
Les