The strength of an alcoholic drink depends upon how much pure alcohol, or ethanol, it contains. Cans or bottles will show the strength as the percentage alcohol by volume or %ABV. The higher the number, the stronger the drink.

We use standard drinks or units to make it easier to know how much alcohol we have drunk. Unfortunately many people are confused about the number of units found in many common drinks.


What's a unit?

A UK unit is 10ml or 8 grams of pure alcohol. The number of units in a drink depends on what you're drinking - how strong it is and how much there is. You may have seen examples of drinks that contain one unit, but these examples are often out of date, for instance:


Half a pint of 3.5% beer/lager/cider is one unit

BUT many continental lagers are closer to 5% while extra strong lagers can be as strong as 9%!


  How alcohol works  

One small (125 ml) glass of wine at 9% is one unit

BUT who uses small glasses? Certainly not pubs and probably not at home either. Plus most wines are now about 11-13%.

  Alcohol units   A 25ml pub measure of spirit at 40% is one unit

BUT some pubs now serve 35ml as standard. Plus other pubs will serve you a double unless you specify otherwise.

To be absolutely sure, use our unit calculator to find out how much alcohol is in your drink.