A standard drink is a measure of alcohol consumption representing a hypothetical beverage which contains a fixed amount of pure alcohol. A 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 drunkenness.
For example, in the United States, a standard drink contains about 14 grams of alcohol. This roughly corresponds to a 12-US-fluid-ounce (350 ml) glass of beer, a 5-US-fluid-ounce (150 ml) glass of 12% wine (no longer the norm, however), or a 1.5-US-fluid-ounce (44 ml) glass of a spirit.[n 1]
Different countries define standard drinks differently. For example, in Australia, a standard drink contains 10 grams of alcohol, but in Japan, it contains nearly 20 grams. In addition, a standard drink is often different from normal serving size in the country in which it is served.
Labeling is usually required to give an indication of alcoholic content of a serving. Australia requires that "the label on a package of an alcoholic beverage must include a statement of the number of standard drinks in the package".
The term "standard drink" was used in the United Kingdom in the first guidelines (1984) that published "safe limits" for drinking, but this was replaced by reference to "alcohol units" in the 1987 guidelines and that term has been used in all subsequent UK guidance. A unit of alcohol is defined as 10 millilitres (8 grams) of pure alcohol. This definition is independent of the strength (% ABV) and amount (volume) of any individual alcoholic beverage. The number of units of alcohol in a bottle or can (and, optionally, the number of units in a typical serving) are indicated on the drink container. Typical servings deliver 1–3 units of alcohol.
Definitions in various countries
The amount of alcohol is stated in the table in both grams and millilitres. The number of standard drinks contained in 500ml of beer of 5% ABV (a typical large drink of beer) is stated for comparison.
|Country||Mass (g)||Volume (mL)||500 mL[n 2] of 5% ABV beer is|
|Australia||10||12.7||2.0 standard drinks|
|Austria||6||7.62||3.2 standard drinks|
|Canada||13.6||17.2||1.4 standard drinks|
|Denmark||12||15.2||1.6 standard drinks|
|Finland||12||15.2||1.6 standard drinks|
|France||10||12.7||2.0 standard drinks|
|Hungary||17||21.5||1.2 standard drinks|
|Iceland||8||10||2.5 standard drinks|
|Ireland||10||12.7||2.0 standard drinks|
|Italy||10||12.7||2.0 standard drinks|
|Japan||19.75||25||1.0 standard drinks|
|Netherlands||9.9||12.5||2.0 standard drinks|
|New Zealand||10||12.7||2.0 standard drinks|
|Poland||10||12.7||2.0 standard drinks|
|Portugal||14||17.7||1.4 standard drinks|
|Spain||10||12.7||2.0 standard drinks|
|UK (unit)||8||10||2.5 units of alcohol|
|United States||14||17.7[n 3]||1.4 standard drinks|
|Switzerland||12||15.2||1.6 standard drinks|
|Germany||14||17.7||1.4 standard drinks|
Calculation of pure alcohol mass in a serving
Pure alcohol mass in a serving can be calculated if concentration, density and volume are known.
For example, 0.35 litre glass of beer with ABV of 5.5% has 15.2 grams of pure alcohol. Pure alcohol has density of 789.24 g/l (at 20 °C).
When 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)|
One should bear in mind that a pint in the UK is 20 UK fluid ounces, whereas a pint in the US is only 16 US fluid ounces.
Time to metabolise
On average, it takes about one hour for the body to metabolise (break down) one standard drink as defined by U.S. guidelines (i.e. 12 ounces of 5% beer, 5 ounces of 12% wine, or 1.5 ounces of 40% liquor). However, this can vary with body weight, sex, age, personal metabolic rate, recent food intake, the type and strength of the alcohol, and medications taken. Alcohol may be metabolised more slowly if liver function is impaired.
- 14 grams of alcohol is 0.6 US fluid ounces or 18 mL.
- rethinkingdrinking.niaaa.nih.gov, US NIH Web site:What's a "standard" drink?
- Guide to Labelling of Alcoholic Beverages
- "Alcohol guidelines, Eleventh Report of Session 2010–12" (PDF). UK Parliament. House of Commons, Science and Technology Committee. 7 December 2011. p. 7. Retrieved 13 February 2015.
- "Drinkaware - What is an alcohol unit?".
- "How long does alcohol stay in your blood?". NHS Choices. Retrieved 11 February 2015.
- UK NHS:How long does alcohol stay in your blood?, reviewed 2013
- ICAP Report 5 - "What is a 'standard drink'". URL:. Accessed on June 19, 2008.
- Population Health Division, Australian Government Department of Health and Ageing The Australian Standard Drink
- Canadian Public Health Association. URL: . 2006.
- paihdelinkki.fi, How to use alcohol wisely
- Landlæknisembættið, Icelandic Directorate of Health
- New Zealand Food Safety Authority
- "Alcohol and Public Health: Frequently Asked Questions". CDC. Retrieved 2011-10-17.