Alcohol Units and Guidelines Explained

A unit is a measure of the alcohol in your drink. It’s the same for beer, wine and spirits, and is expressed as grams of ethanol (1). In the UK, a unit contains eight grams (2).

The purpose of a unit is to provide consistency across beverage types and help translate the science behind drinking and health into something easily understood. This is important for providing drinking guidelines and advice. The UK Chief Medical Officer’s guideline for both men and women is not to drink more than 14 units a week on a regular basis, to minimise any health risks from alcohol (3).

Standard unit sizes are different across countries, but they always ensure the amount of alcohol is the same in any beverage

Not all countries use the same unit size as the UK ⁽¹⁾. Nevertheless, in each case, the same measure applies whether you’re drinking beer, wine or spirits.

Some places, like the US, also refer to a ‘standard drink’ rather than a ‘unit’.

For example:

• A standard unit in the UK contains 8 grams of ethanol

• In Australia and France, the standard is 10 grams

• A Mexican standard drink contains 13 grams

• There are 14 grams of ethanol in a standard drink in the US, Argentina and Chile

Units can help you understand drinking guidelines

It’s true that a unit doesn’t always translate into how drinks are actually served. For example, many cocktails contain several different spirits or are mixed with wine or champagne, so they’ll most likely contain more alcohol than in a standard unit. Also, since wine comes in different strengths, and glasses are available in different sizes, the amount of alcohol you drink may not be standard. This is especially true if you’re at home and top up your glass before you’re finished.

However, a unit is still a useful concept. Since the concentrations of drinks are different, a unit ensures that the amount of ethanol in a serving is always the same. This is important for sharing information about drinking and its effects on your health.

Using a standard unit allows for guidance on levels of drinking, regardless of whether the drinks are spirits, wine or beer. Plus, advice is generally given in terms of the number of units it’s best not to exceed in a day or a week, or on an occasion.