How does my drinking add up

With so many different drinks and glass sizes, from shots to pints – not to mention bottles – it's easy to get confused about how many units are in your drink.

An easy mistake is to think one drink equals one unit. It doesn't.

Depending on the type of drink and the glass size the real amount of alcohol can often be considerably more.

Units are a way to describe the quantity of pure alcohol in a drink. This was developed to help people understand how much alcohol they are drinking, because it is the alcohol itself that is harming people’s health.

The number of units in a drink is based on the bottle or glass size, as well as the strength of the alcohol in the drink

Alcohol strength at a glance.png
Alcohol units at a glance NHS Health Scotland

Calculating units

The number of units in a drink can be calculated from the ABV (alcohol by volume) and the size of the drink.

The higher the ABV, the stronger the drink.

You can find the ABV on labels of alcoholic drinks:

  • it's sometimes written as "vol" or "alcohol volume"
  • the number of units in a bottle is often illustrated on the back of the bottle
  • bar staff can explain alcohol content too.

For example, wine that says "12% ABV" or "alcohol volume 12%" means 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 (measured as a percentage) and dividing the result by 1,000.

  • strength (ABV) x volume (ml) ÷ 1,000 = units

So, to work out the number of units in a pint (568ml) of strong lager (ABV 5.2%):

  • 5.2 (%) x 568 (ml) ÷ 1,000 = 2.95 units

Based on the sample range of drinks above, fourteen units is equivalent to 6 pints of beer, 6 glasses of wine or 7 double measures of spirits.

Still not sure about units? Try the Scottish Government's alcohol unit generator and alcohol unit calculator.