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One unit of alcohol is ½ a pint of 4% beer, one small pub measure of spirits or ⅔ of a small glass of 12.5% wine. Men should drink no more than 4 units a day, women 3.

Units are a simple way of expressing the quantity of pure alcohol in a drink. One unit equals 10ml or 8g of pure alcohol, which is around the amount of alcohol the average adult can process in an hour. This means that within an hour there should be, in theory, little or no alcohol left in the blood of an adult, although this will vary from person to person.

The number of units in a drink is based on the size of the drink as well as its alcohol strength. For example, a pint of strong 6.5% lager contains 3 units of alcohol, whereas the same volume of standard 4% lager has just over 2 units.

Be sure to read our How long does alcohol stay in my system? page to work out how to calculate how long alcohol will stay in your body.


  • using units is a simpler way of representing a drink’s alcohol content, which is usually expressed by the standard measure ABV, which stands for alcohol by volume
  • wine that says “12% ABV” or “alcohol volume 12%” means that 12% of the volume of that drink is pure alcohol
  • you can work out how many units there are in any drink by multiplying the total volume of a drink (in ml) by its ABV (which is measured as a percentage) and dividing the result by 1,000. For example, to work out the number of units in a pint (568ml) of strong lager (ABV 5.2%): 568 (ml) x 5.2 (%) ÷ 1,000 = 2.95 units

Source: NHS Choices


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  • Recommended Safe Limits of Alcohol @

    Excerpt: The more you drink above these limits, the greater the risk of developing serious problems such as: liver disease (cirrhosis or hepatitis); stomach and pancreas disorders; depression; anxiety; sexual difficulties; muscle and heart muscle disease; high blood pressure; damage to nervous tissue; serious accidents; some cancers; obesity (alcohol has many calories).

  • Alcohol units | Your guide to alcohol units & measures @

    Excerpt: The alcoholic content in the same types of drinks can vary a lot. Warm, flat ale may have been our national drink 30 years ago, but imported lagers have gradually become more and more popular, and their alcohol strength can be quite a bit higher than ale. For example, some ales have an alcohol content of 3.5%. But stronger continental lagers can be 5% ABV, or even 6%. This means that just one pint of strong lager can equate to more than three units of alcohol – almost your daily recommended guideline if you are a man.

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