Unit of alcohol - Definition and Overview

In the UK a system of units of alcohol is employed for an approximate measure of the amount of alcohol in different drinks.

Formula

A unit of alcohol is equivalent to 10 millilitres (or approximately 8 grams) of pure ethanol, the active chemical ingredient in alcoholic beverages.

The number of units of alcohol in a drink can be determined by multiplying the volume of the drink (in millilitres) by its percentage ABV, and dividing by 1000.

Thus a pint (568ml) of beer at 4% ABV contains

<math>\frac{(568 \times 4)}{1000} = 2.3\mbox{ units}<math>

Quantities

As a rough guide:

• A glass of wine or sherry, a single measure of spirits and a half pint of beer each contain about one unit, or 8 g (0.25 oz) of 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

Since 1995 the UK government has advised that regular consumption of between three and four units a day for men and between two and three units a day for women would not pose significant health risks, but that consistently drinking four or more units a day (men) or three or more units a day (women) is not advisable. The difference between genders is given due to the (typically) lower weight and water-to-body-mass-ratio of women.

See also

• standard drink