A normal glass of
wine or sherry
?, a single measure of
spirits and a
half pint of
beer each contain about one unit, or 8g (1/4oz)
alcohol.
A large glass of red or white wine or half a pint of
cider contains
about 12g (3/8oz), or one and a half units. However strong
lager may contain as much as two units per half pint.
Limits
It is recommended twenty-one units maximum a week for men and 14 units for women. The difference is accounted for because of the (typically) lower weight and water-to-body-mass-ratio of women.
In Australia, we have a similar concept known as 'standard drinks'. A glass of wine or a shot of spirits are considered a standard drink. A 375mL bottle of beer can vary from 0.9 standard drinks for light beer to 1.4 for normal beer.