What's a standard drink?
A standard drink isn’t usually the same as a glass of wine or beer poured in a pub or at home.
One standard drink in New Zealand contains 10 grams of pure alcohol. The standard drink measure is a simple way for you to work out how much alcohol you are drinking.
The law requires all bottles, cans and casks of alcoholic drinks to be labelled with how many standard drinks they contain. Look at the label for wording about standard drinks or for a standard drinks image. The number inside the image tells you approximately how many standard drinks in a container.
The number of standard drinks in different alcoholic drinks varies. It depends on the size of the container and the amount of alcohol it contains.
Check the standard drinks on the label to work out how many drinks you are serving out of each bottle, can or cask.
For example, if a standard drink label on a bottle of wine says it contains eight standard drinks, and that bottle has only filled four big glasses, each of those glasses contains approximately two standard drinks or 20 grams of alcohol.
If you want information about the number of standard drinks in different drinks, download the Straight up guide to standard drinks pamphlet (PDF, 438KB).
Why are standard drinks important?
Looking at labels and counting standard drinks is a reliable way of knowing how much alcohol you are drinking.
Counting glasses, bottles, or cans of alcohol can be misleading because each one may contain varying amounts of alcohol.
Whereas one standard drink always contains the same amount of alcohol (10 grams) despite the container size or alcohol type.
An average person’s liver can only break down around one standard drink of alcohol per hour.
Low-risk alcohol drinking advice from Te Hiringa Hauora/Health Promotion Agency is based on standard drinks.
How are standard drinks calculated?
The formula to work out the number of standard drinks in an alcoholic drink is:
Amount of drink in litres (the volume of the container) multiplied by the percent by volume of alcohol (%) multiplied by 0.789 (which is the density of ethanol at room temperature) equals the number of standard drinks.
For example a 500ml bottle of beer which is 5% alcohol by volume:
0.5 multiplied by 5 multiplied by 0.789 equals 1.97 standard drinks
0.5 x 5 x 0.789 = 1.97 (approx 2 standard drinks)
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