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
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
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out of date, for instance: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%!
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%.
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.