How Much Alcohol Is in a Standard Drink or Unit?

What Is a Regular Serving?

Woman drinking white wine on patio
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If you are considering controlling or moderating your drinking, or if you have read or heard of the purported health benefits of alcohol, and are thinking of incorporating alcohol into your regular diet, it is helpful to understand how much alcohol you should be and are consuming.

The only way to know your alcohol intake is to figure out how much alcohol is contained in beverages you are drinking. In an effort to make this easier, several countries have introduced the concept of a "standard" drink, or "unit of alcohol." A standard drink is a typical serving of a commonly consumed beverage, which contains a specific amount of alcohol.

Use of standard drinks, or units, is intended to give a common understanding of what we mean by a "drink," so, for example, a doctor can advise you to have no more than a certain number of drinks per day or per week. Difficulties arise, however, as a result of different countries defining drinks with widely variable amounts of alcohol, and as a result of widely different strengths of drinks. Some beers, for example, are two or three times as strong as others.

Variation Between Countries

The amount of alcohol in a standard drink or unit varies according to different countries. This is something you should be aware of if you travel, especially if your doctor has limited the number of drinks you should consume.

There are two sources of information on standard drinks: those specified by governments, and those used in research studies on alcohol use. Ideally, they should be the same, but look at the variation among the alcohol contents of standard drinks of some countries that have published research on drinking:

  • USA: Government standard is 14 grams of alcohol per drink, but studies report drinks ranging from 9.3 to 13.2 grams of alcohol per drink.
  • Canada: One study reports 13.6 grams of alcohol per drink.
  • UK: Government standard is 8 grams of alcohol per drink, but studies report drinks ranging from 8 to 10 grams of alcohol per drink.
  • Rest of Europe: Studies report a range of alcohol contents per drink from 8.7 to 11 grams.
  • Australia and NZ: Government standard is 10 grams of alcohol per drink, but studies report a range of alcohol contents per drink from 6 to 11 grams.
  • Japan: Studies report a range of alcohol contents per drink from 21.2 to 28 grams.

Part of the reason for the great variation is based on cultural factors -- standard drinks reflect what is considered normal or typical in that country.

Variation Between Drinks

The amount of an alcoholic beverage also varies considerably, depending on the type and strength of the drink. Sometimes you can find out the strength of the drink by looking at the label, but drinks manufacturers are not always required to include the alcohol content. Labels can also be confusing, because sometimes the alcohol contents is displayed by weight, and sometimes by volume -- weight seems less than volume because alcohol is lighter than water (the weight of alcohol is 0.8 of its volume).

Here is an idea of the range of alcohol contents (by volume) in different drinks:

  • Non-Alcoholic or Low Alcohol Beer (not the same as lite beer): 0% to 0.5%
  • Beer: Typically around 5% alcohol, but can range from 2.5% to 12%
  • Wine: Typically around 12%, but can range from 4% in wine coolers to 19% in dessert wines.
  • Liquor: Typically around 40%, but can range from 20% in peach schnapps to 95% in everclear.

Variation Between Glasses

Most importantly, you should know how much your home drinking glasses actually contain, and educate yourself on estimating how much various sizes and shapes of glasses contain. In general, the narrower the glass, the less it contains, while the wider the bowl, particularly at the bottom, the more it contains. This may sound like stating the obvious, but a little experimentation with different shapes and sizes of glasses and a measuring jug may surprise you.

In fact, research has shown that we are poor at estimating how much we are pouring, particularly with wine and spirits drinks. The growth in popularity and advertising of ready-mixed drinks which contain high levels of alcohol in fruit-flavored, soda-like drinks, or “alcopops” is a particular concern. As well as being marketed to younger drinkers, the fact that they look and taste like a soft drink creates even greater likelihood that you will underestimate the actual amount of alcohol you have consumed.

To Err Is Human... Especially With Alcohol

Probably the biggest factor in misjudging the amount of alcohol in your home-poured servings is that of human error. If you enjoy the taste and effects of alcohol and let's face it, most drinkers do, you will probably kid yourself that your "standard" drinks are less than they actually are. Furthermore, you aspire to be a generous host, you don't want to waste good wine, so you finish the bottle, and you may consider restaurant, bar or pub servings to be stingy -- some people feel a standard drink is little more than a dirty glass.

The bottom line is that if you care about your health, if you wish to maintain your dignity, and if you genuinely do not want to be addicted to alcohol, you will limit your intake extremely carefully. The inability to stop drinking once you have started and denial around the use alcohol are central characteristics of alcohol addiction. Controlling your drinking is something that you, and you alone, must take responsibility for.

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