# Standard drink

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.

The standard drink is used in relation to recommendations about alcohol consumption and its relative risks to health. Many government health guidelines specify low to high risk amounts in units of grams of pure alcohol per day, week, or single occasion. The concept of the standard drink is meant to help visualize and estimate the absolute alcohol content of various drink concentrations and serving sizes.

For example, in the United States, a standard drink contains about 14 grams of alcohol.[1] This corresponds to a 12-US-fluid-ounce (350 mL) glass of beer, a 5-US-fluid-ounce (150 mL) glass of 12% ABV (alcohol by volume) wine, or a 1.5-US-fluid-ounce (44 mL) so-called "shot" of spirit.[2] 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% [3]). 80 proof is still the standard for spirits, though higher alcohol content is common.

Different countries define standard drinks differently. For example, in Australia, a standard drink contains 10 grams of alcohol,[4] 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.[5]

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".[4]

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 units of alcohol in the 1987 guidelines and that term has been used in all subsequent UK guidance.[6] A unit of alcohol is defined there as 10 millilitres (8 grams) of pure alcohol.[7][8] 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.[9]

## Definitions in various countries

These are the amounts of alcohol defined by several countries for standardising measurement of drinking levels and providing public health information. As well as choosing different quantities for a "standard" drink, some 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. There is no single standard but more countries have adopted the WHO "standard drink" of 10g alcohol than have adopted any other amount[10]. The terminology for the unit also varies, as shown in the Notes column.

CountryMass (g)Volume (mL)Notes
Australia[10][11]1012.7
Austria[10][12]2025.3
Denmark[10][12]1215.2
Finland[15]1215.2
France[10]1012.7
Germany[10][16]1113.8standardglas defined as containing 10 - 12g (central value used here)
Hong Kong[17]1012.7
Hungary1721.5
Iceland[10][18]810áfengiseining defined as 8g but treated as equivalent to 10mL
Ireland[10][19]1012.7
Italy[10]1012.7unita standard defined as 10mL
Japan19.7525go
Netherlands[12]1012.7
New Zealand[10][20][21]1012.7
Poland[10]1012.7
Portugal[10]1113.810 - 12g (central value used here)
Spain[10]1012.7
Switzerland[10]1215.2
United Kingdom[10][22]810unit of alcohol defined as 10mL but treated as equivalent to 8g
United States[10][23]1417.7standard drink defined as 0.6 fl oz (US) or 14g

## Calculation of pure alcohol mass in a serving

Pure alcohol mass in a serving can be calculated if concentration, density and volume are known.

${\displaystyle Pure\ alcohol\ mass=volume\ \times \ (alcohol\ by\ volume\ \times \ volumetric\ mass\ density)}$

For example, a 350 ml glass of beer with an ABV of 5.5% has 15.19 grams of pure alcohol, which has a density of 789.24 g/L (at 20 °C).

${\displaystyle 350\ mL\times \ (0.055\ \times \ 0.78924\ g/ml)\approx 15.19\ g}$
or
${\displaystyle 0.35\ L\times (0.055\times 789.24\ g/L)\approx 15.19\ g}$

When drink size is in fluid ounces (which differ between the UK and the US), the following conversions can be used:

CountryVolume of fl. oz. (mL)Mass of fl. oz. of alcohol (g)
UK28.4122.42
US29.5723.34

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. However, as 1 imperial fl. oz. ≈ 0.961 US fl. oz., this means 1 imperial pint ≈ 1.201 US pints (i.e. 0.961 x 20/16) instead of 1.25 US pints.

## Time to metabolise

On average, it takes about one hour for the body to metabolise (break down) one UK unit of alcohol, 10 ml (8 grams). 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.[9]

To determine time to metabolise, multiply one hour by the number of alcohol units in the local definition of a standard drink. For example, in the United States one standard drink contains 14 grams = 1.75 units of alcohol, and so takes the body about an hour and three-quarters to process.

## References

Explanatory notes

Citations

1. 14 grams of alcohol is 0.6 US fluid ounces or 18 mL.
2. rethinkingdrinking.niaaa.nih.gov, US NIH Web site:What's a "standard" drink?
3. Alcohol: the Devil is in the Details {So why won’t major American wine media run %s in reviews?}
4. Guide to Labelling of Alcoholic Beverages
5. Mongan, Deirdre; Long, Jean (May 22, 2015). "Standard drink measures throughout Europe; peoples' understanding of standard drinks and their use in drinking guidelines, alcohol surveys and labelling" (PDF). Reducing Alcohol Related Harm. p. 8. Retrieved September 26, 2017.
6. "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.
7. "Drinkaware - What is an alcohol unit?".
8. "How long does alcohol stay in your blood?". NHS Choices. Retrieved 11 February 2015.
9. UK NHS:How long does alcohol stay in your blood?, reviewed 2013
10. Kalinowski, A.; Humphreys, K. (2016-04-13). "Governmental standard drink definitions and low‐risk alcohol consumption guidelines in 37 countries". Addiction (Abingdon, England). 111 (7): 1293–8. doi:10.1111/add.13341. PMID 27073140.
11. Population Health Division, Australian Government Department of Health and Ageing The Australian Standard Drink
12. "Drinking Guidelines: General Population". IARD.org. International Alliance for Responsible Drinking. Retrieved 23 June 2016.
13. Canadian Public Health Association. URL: . 2006.
14. Centre for Addiction and Mental Health / Centre de toxicomanie et de santé mentale Low-Risk Drinking Guidelines
15. paihdelinkki.fi, How to use alcohol wisely
16. "Was ist ein Standardglas?" [What is a standard drink?]. Alkohol? Kenn dein Limit. (in German). Bundeszentrale für gesundheitliche Aufklärung. Retrieved September 26, 2017.
17. Department of Health Alcohol and Health: Hong Kong Situation
18. Landlæknisembættið, Icelandic Directorate of Health
19. Hope, A. (2009). A Standard Drink in Ireland: What strength? (PDF). Health Service Executive. Retrieved 2 February 2015.
20. New Zealand Food Safety Authority Archived 2008-07-04 at the Wayback Machine
21. Alcohol Advisory Council of New Zealand (ALAC) What's in a Standard Drink
22. PRODIGY Knowledge (Department of Health) Alcohol and Sensible Drinking Archived 2006-09-25 at the Wayback Machine
23. "Alcohol and Public Health: Frequently Asked Questions". CDC. Retrieved 2011-10-17.