A standard drink or (in the UK) unit of alcohol is a measure of alcohol consumption representing a fixed amount of pure alcohol. The notion is used in relation to recommendations about alcohol consumption and its relative risks to health. It helps to inform alcohol users.
A hypothetical alcoholic beverage sized to one standard drink varies in volume depending on the alcohol concentration of the beverage (for example, a standard drink of spirits takes up much less space than a standard drink of beer), but it always contains the same amount of alcohol and therefore produces the same amount of intoxication. Many government health guidelines specify low to high risk amounts in units of grams of pure alcohol per day, week, or single occasion. These government guidelines often illustrate these amounts as standard drinks of various beverages, with their serving sizes indicated. Although used for the same purpose, the definition of a standard drink varies very widely from country to country.
Labeling beverages with the equivalent number of standard drinks is common in some countries.
Definitions in various countries
The definition of what constitutes a standard drink varies very widely between countries, with what each country defines as the amount of pure alcohol in a standard drink ranging from 8 to 20 grams (10 to 25 ml).
The sample questionnaire form for the World Health Organization's Alcohol Use Disorders Identification Test (AUDIT) uses , and this definition has been adopted by more countries than any other amount. Some countries choose to base the definition on mass of alcohol (in grams) while others base the unit on the volume (in ml or other volume units). For comparison, both measurements are shown here, as well as the number of standard drinks contained in of 5% ABV beer (a typical large size of beer in Europe, slightly larger than a US pint of 473 mL). The terminology for the unit also varies, as shown in the Notes column.
+ Amount of pure alcohol (in grams or millilitres) contained in a standard drink, as defined in different countries. Country Mass(g) Volume(mL) Ratio toWHO AUDIT'sexample(10 g) Is 10 g Notes Albania 10 12.7 Argentina 14 17.7 AustraliaPopulation Health Division, Australian Government Department of Health and Ageing The Australian Standard Drink 10 12.7 Austria 20 25.3 Benin 14 17.7 Bosnia and Herzegovina 10 12.7 CanadaCanadian Public Health Association. URL: . 2006.Centre for Addiction and Mental Health / Centre de toxicomanie et de santé mentale Low-Risk Drinking Guidelines 13.6 or13.45 or13.5 17.2 or 17 or This specific unit is computed based on the oz definition as: bottle of 5% alcohol beer, cider or cooler shot of 40% hard liquor (vodka, rum, whisky, gin etc.) glass of 12% wine. Costa Rica 8 10 Croatia 10 12.7 Denmark 12 15.2 Estonia 10 12.7 Fiji 10 12.7 Finlandpaihdelinkki.fi, How to use alcohol wisely 12 15.2 France 10 12.7 Georgia 10 12.7 Germany 11 13.8 Standardglas defined as containing 10–12 g (central value used here) Guyana 8 10 Hong KongDepartment of Health Alcohol and Health: Hong Kong Situation 10 12.7 Hungary 17 21.5 Iceland 8 10 áfengiseining defined as 8 g but treated as equivalent to 10 mL Ireland 10 12.7 Italy 12 15.2 unità standard defined as 12 g Japan 19.75 25 "".MHLW's conventional unit,based on 1 gō (unit) ( mL) of sake.Japan1012.7 "". Introduced by 2010 Referring web page: to align with the WHO AUDIT,and to avoid the conventional "" (20 g) which gave a false impression of "minimum amount to drink".Sometimes this amount (around 10 g) is also called "", a term which traditionally meant 20 g. Latvia 12 15.2 Luxembourg 10–12 12.7–15.2 - Malta 8 10 Mexico 10–13 12.7–16.5 - Namibia 10 12.7 Netherlands 10 12.7 New ZealandNew Zealand Food Safety Authority Alcohol Advisory Council of New Zealand (ALAC) What's in a Standard Drink 10 12.7 North Macedonia 14.2 18 Norway 12.8 15 Philippines 12 15.2 Poland 10 12.7 Portugal 11 13.8 10–12 g (central value used here) Russia 10 12.7 Saint Vincent and the Grenadines 14 17.7 Seychelles 8 10 Singapore 10 12.7 Slovenia 10 12.7 South Korea 8 10 Spain 10 12.7 Sweden 12 15.2 standardglas corresponds to 33 cl 5% beer, 13 cl wine, or a drink or shot based on 4 cl 40% liquor Switzerland 12 15.2 Taiwan (ROC) 10 12.7 Thailand1012.71 Ukraine 10 12.7 United KingdomPRODIGY Knowledge (Department of Health) Alcohol and Sensible Drinking 8 10 unit of alcohol defined as 10 mL but treated as equivalent to 8 g. United States 14 17.7 standard drink defined as pure ethanol, approximately 14 g Uruguay 10 12.7
Calculation of pure alcohol by mass
It is possible to calculate the pure alcohol mass in a serving from the concentration, density of alcohol, and volume:
For example, a glass of beer with an ABV of 5.5% contains 19.525 ml of pure alcohol, which has a density of 0.78945 g/mL (at 20 °C), and therefore a mass of .
or
When the drink size is in fluid ounces (which differ between the UK and the US), the following conversions can be used: Country Volume of fl. oz. (mL) Mass of fl. oz. of alcohol (g) UK 28.41 22.43 US 29.57 23.35
One should bear in mind that a pint in the UK is 20 imperial fluid ounces, whereas a pint in the US is 16 US fluid ounces, and that 1 imperial fl. oz. ≈ US fl. oz.: this means that 1 imperial pint ≈ US pints.
Calculation of units of alcohol by volume
Calculating alcoholic content in countries that use units of alcohol is straightforward, as the volume multiplied by the Alcohol by volume (ABV) gives the alcohol content. In the UK, one unit of alcohol equals one percentage point per litre, of any alcoholic beverage.
The standard UK units of alcohol in a drink can be determined by multiplying the volume of the drink (expressed in litres) by its percentage ABV. For example, a standard bottle of wine at 12% ABV contains:
One UK standard measure of spirits (25ml, 0.025 L) at 40% ABV contains:
One imperial pint (568ml, 0.568 L) of beer at 4% ABV contains:
In the UK, both volume and ABV are usually given on bottles, drinks menus and so on, and so are easy to retrieve.
Reference standard drinks
A standard drink is often different from a normal serving in the country in which it is served. For example, in the United States, a standard drink is defined as of ethanol per serving, which is about 14 grams of alcohol.14 grams of alcohol is 0.6 US fluid ounces or ~18 mL. → Ethanol listed as 0.78945 g/mL @ 20°C (68°F), 0.6 US fl oz × 29.57 mL/US fl oz = 17.742 ml; 0.78945 g/mL × 17.742 mL = 14.006gHaynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. p. 3.246. ISBN 1-4398-5511-0. This corresponds to a can of 5% beer, a glass of 12% ABV (alcohol by volume) wine, or a so-called "shot" of spirit, assuming that beer is 5% ABV, wine is 12% ABV, and spirits is 40% ABV (80 proof). Most wine today is higher than 12% ABV (the average ABV in Napa Valley in 1971 was 12.5%), hence will be more than a standard drink. Similarly, although 40% ABV is standard for spirits, the amount of spirit in a mixed drink varies widely.
Beers Half an imperial pint of beer with 3.5% ABV contains almost exactly one UK unit; however, most beers are stronger. In pubs in the United Kingdom, beers generally range from 3.5 to 5.5% ABV, and continental lagers start at around 4% ABV. An imperial pint of such lager (at 5.2% ABV) contains almost 3 units of alcoholThe volume of the drink in litres multiplied by its percentage strength in ABV give the number of units. In this case, ; i.e., almost 3 units. rather than the oft-quoted 2 units. Stronger beer (6–12%) may contain 2 UK units or more per imperial half pint. A half-litre (500 ml) of standard lager or ale (5%) contains 2.5 UK units. One litre (1000 ml) of typical Oktoberfest beer (5.5–6%) contains 5.5–6 UK units of alcohol. A beer bottle is typically between , approximately 1.7 UK units at 5%. can of light beer (2.7% alcohol) = 0.8 Australian standard drinks can of mid-strength beer (3.5% alcohol) = 1 Australian standard drink can of full strength beer (4.8% alcohol) = 1.4 Australian standard drinks of 5% ABV beer = 1 US standard drink
Wines
A "medium" glass ( of 12% ABV wine contains around 2.1 units of alcohol. However, British pubs and restaurants often supply larger quantities (large glass ≈ ), which contain 3 units. Red wines often have a higher alcohol content (on average 12.5%, sometimes up to 16%). Even though the sizes of wine glasses are defined in UK law, the terms large, medium, standard, etc. are not defined in law. A bottle of 12% ABV wine contains 9 units; 16% ABV wine contains 12 units; a fortified wine such as port at 20% ABV contains 15 units. glass of wine (13.5% alcohol) = 1 Australian standard drink glass of wine (13.5% alcohol) = 1.5 Australian standard drinks One glass of 12% ABV table wine is one US standard drink.
Fortified wines A small glass () of sherry, fortified wine, or cream liqueur (≈20% ABV) contains about one unit.
Spirits Most spirits sold in the United Kingdom have 35%-40% ABV. In England, a single pub measure () of a spirit contains one unit. However, a larger measure is increasingly used (and in particular is standard in Northern Ireland), which contains 1.4 units of alcohol at 40% ABV. Sellers of spirits by the glass must state the capacity of their standard measure in ml.
In Australia, a shot of spirits (40% ABV) is 0.95 standard drinks.
In the US, one shot of 80 proof liquor is , which is one US standard drink.
Mixed spirits and alcopops can of pre-mix spirits (approx. 5% alcohol) = 1.7 Australian standard drinks can pre-mix spirits (approx. 7% alcohol) = 2.4 Australian standard drinks According to Alcohol and You Northern Ireland resource website, "Most alcopops contain 1.1–1.5 units per bottle. For example, a normal bottle of WKD contains 1.1 units, whereas Bacardi Breezer and Smirnoff Ice both contain 1.5 units of alcohol."
Recommended maximum
From 1992 to 1995, the UK government advised that men should drink no more than 21 units per week, and women no more than 14. (The difference between the sexes was due to the typically lower weight and water-to-body-mass ratio of women). The Times claimed in October 2007 that these limits had been "plucked out of the air" and had no scientific basis.Drink limits ‘useless’, The Times, 20 October 2007
This was changed after a government study showed that many people were in effect "saving up" their units and using them at the end of the week, a form of binge drinking. Since 1995 the advice was that regular consumption of 3–4 units a day for men, or 2–3 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. These guidelines were updated in August 2016 by the Chief Medical Officers of each of the four regions of the UK. The emphasis shifted from a level that does not pose risk towards levels that pose a low risk. This shift in emphasis was on the basis of an evaluation of evidence about the levels and types of health harm from alcohol. In brief, the weekly guideline was no more than 14 units for both men and women, ideally spread evenly over three or more days, with alcohol-free days included. On a single occasion, the emphasis was on limiting drinks on a single occasion, and not drinking at all during pregnancy. Subsequently, research has suggested that the level of consumption that minimises health loss is zero, i.e. to protect health, it is better not to drink alcohol. However, a 2025 review by the National Academies of Sciences, Engineering, and Medicine concluded that while heavy alcohol use is clearly harmful, moderate alcohol consumption was associated with lower all-cause mortality compared to never consuming alcohol.
Relation to blood alcohol content