ALCOHOL BASICS

What is a standard drink?
Not every serving is one.

A standard drink is a country-specific reference amount of pure alcohol—not a particular glass, can, bottle, or cocktail. Serving volume and alcohol by volume (ABV) determine the amount.

Calculate a drink from its label

What does “standard drink” mean?

A standard drink is a public-health reference for a defined amount of pure alcohol. It helps compare beer, wine, spirits, and mixed drinks that may look very different but contain a similar alcohol amount.

It is not the same as a serving. A large, strong beer can contain several standard drinks, while a smaller lower-ABV drink can contain less than one. The product label gives the two numbers that matter: volume and ABV.

Volume × ABV determines alcohol amount. A serving size or beverage name on its own does not tell you the number of standard drinks.

Standard-drink definitions by country

Country / termPure alcohol referenceSource-linked local guide
United States14 g (0.6 fl oz)U.S. standard drinks
Australia10 gAustralia standard drinks
United Kingdom / unit8 g (10 ml)UK alcohol units
Canada13.45 g (17.05 ml)Canada standard drinks
New Zealand10 gNew Zealand standard drinks
Ireland10 gIreland standard drinks
Singapore10 gSingapore standard drinks

These are measurement references, not recommendations to drink. The same product can be reported as a different number of local units because the reference amount changes by country. For a compact comparison with direct tool routes, see alcohol units by country.

How to calculate standard drinks from a label

First estimate pure alcohol in grams:

volume in ml × ABV as a decimal × 0.789 = grams of pure alcohol

Then divide that total by the local reference in the table. For example, a 355 ml drink at 5% ABV contains about 14 g of pure alcohol: one U.S. standard drink, about 1.4 Australian, New Zealand, Irish, or Singapore standard drinks, and about 1.75 UK alcohol units.

Use the standard-drinks calculator for one serving, the container calculator for a full can or bottle, or the alcohol grams calculator to compare the common pure-alcohol measure.

Why ABV and container size both matter

ABV is the percentage of a beverage that is alcohol by volume. Two equal-size beers can contain very different alcohol amounts if one is 4% ABV and the other is 8% ABV. Likewise, two drinks with the same ABV can contain different alcohol amounts when their containers differ in size. Check both numbers printed on the product.

This is especially useful for strong beers, large cans, bottles of wine, mixed drinks, and canned cocktails. Product type is only a starting point; use the label whenever it is available.

What a standard-drink count cannot tell you

A standard-drink count does not measure BAC, impairment, tolerance, health effects for an individual, or whether it is safe or legal to drive. For BAC terminology and measurement limits, read What is BAC?. If alcohol is involved, arrange a sober way home rather than relying on a count or online estimate.

Sources and review

  1. U.S. National Institute on Alcohol Abuse and Alcoholism: What is a standard drink?
  2. NHS: alcohol units and calculation
  3. Australian Government: standard drinks guide
  4. Canadian Centre on Substance Use and Addiction: Canada’s guidance on alcohol and health
  5. Health New Zealand: drinking responsibly
  6. HSE Ireland: alcohol guidance
  7. Singapore HealthHub: alcohol information