A standard drink is a fixed amount of pure alcohol, used to compare a beer, a glass of wine and a shot on the same scale. How much alcohol it holds depends on the country: 14 g in the USA, 10 g in Australia, 12 g in Sweden, and in the UK, which counts in units instead, 8 g. The World Health Organization uses 10 g as its reference, and that is the most common definition worldwide.
So “one drink” is not the same thing everywhere. A US standard drink is 1.4 Australian standard drinks, or about 1.8 UK units.
Standard drink sizes by country
| Country | Name | Pure alcohol per drink |
|---|---|---|
| Austria | — | 20 g |
| USA | standard drink | 14 g |
| Canada | standard drink | 13.45 g |
| Sweden | standardglas | 12 g |
| Denmark | genstand | 12 g |
| Finland | annos | 12 g |
| Italy | unità alcolica | 12 g |
| Australia | standard drink | 10 g |
| New Zealand | standard drink | 10 g |
| Ireland | standard drink | 10 g |
| France | verre standard | 10 g |
| Spain | unidad de bebida estándar | 10 g |
| Netherlands | standaardglas | 10 g |
| WHO reference | 10 g | |
| UK | unit | 8 g (10 ml) |
| Iceland | — | 8 g |
A 2016 survey of 37 governments found definitions ranging from 8 g to 20 g, with 10 g the most common. The difference matters whenever you read a drinking guideline from another country: “no more than ten a week” means 100 g in Australia but 120 g in Sweden.
What one standard drink looks like
- USA: 12 fl oz (355 ml) of 5 % beer, 5 fl oz (148 ml) of 12 % wine, or 1.5 fl oz (44 ml) of 40 % spirits. (NIAAA)
- Canada: 341 ml of 5 % beer or cider, 142 ml of 12 % wine, or 43 ml of 40 % spirits. (CCSA)
- Sweden: 33 cl of strong beer, 50 cl of light beer (folköl), 12–15 cl of wine, or 4 cl of spirits. (Systembolaget)
- UK: one unit is a single 25 ml measure of 40 % spirits. A 175 ml glass of wine is about 2.1 units, and a pint of stronger beer about 3. (NHS)
How to work out the grams in any drink
You only need the volume and the strength (ABV) printed on the label:
grams of alcohol = volume in ml × ABV ÷ 100 × 0.789
The 0.789 is the density of ethanol: a millilitre of pure alcohol weighs 0.789 g. Divide the result by your country’s standard drink size to get the number of standard drinks.
Take a 330 ml bottle of beer at 5 %:
330 × 5 ÷ 100 = 16.5 ml of pure alcohol
16.5 × 0.789 = 13.0 g
That is 0.9 of a US standard drink (13.0 ÷ 14), 1.3 Australian standard drinks (13.0 ÷ 10) and 1.1 Swedish standardglas (13.0 ÷ 12). UK units work from millilitres rather than grams: 16.5 ml ÷ 10 = 1.65 units.
Common drinks in standard drinks
| Drink | Pure alcohol | US (14 g) | Australia (10 g) | Sweden (12 g) | UK units |
|---|---|---|---|---|---|
| Beer, 330 ml bottle, 5 % | 13.0 g | 0.9 | 1.3 | 1.1 | 1.7 |
| Beer, 12 oz / 355 ml can, 5 % | 14.0 g | 1.0 | 1.4 | 1.2 | 1.8 |
| Beer, 500 ml, 5 % | 19.7 g | 1.4 | 2.0 | 1.6 | 2.5 |
| Beer, UK pint (568 ml), 4 % | 17.9 g | 1.3 | 1.8 | 1.5 | 2.3 |
| Beer, UK pint (568 ml), 5 % | 22.4 g | 1.6 | 2.2 | 1.9 | 2.8 |
| Wine, 150 ml, 12 % | 14.2 g | 1.0 | 1.4 | 1.2 | 1.8 |
| Wine, 175 ml, 13 % | 17.9 g | 1.3 | 1.8 | 1.5 | 2.3 |
| Wine, 250 ml, 13 % | 25.6 g | 1.8 | 2.6 | 2.1 | 3.3 |
| Wine, 750 ml bottle, 13 % | 76.9 g | 5.5 | 7.7 | 6.4 | 9.8 |
| Spirits, 25 ml, 40 % | 7.9 g | 0.6 | 0.8 | 0.7 | 1.0 |
| Spirits, 40 ml, 40 % | 12.6 g | 0.9 | 1.3 | 1.1 | 1.6 |
| Spirits, 1.5 oz / 44 ml, 40 % | 13.9 g | 1.0 | 1.4 | 1.2 | 1.8 |
The label is what counts. A craft IPA at 7 % in a 440 ml can holds 24 g, about 1.7 US standard drinks, and a home-poured glass of wine is often closer to 250 ml than 150 ml.
Standard drinks and drinking guidelines
Health guidelines are written in the local unit, so the same-sounding advice means different amounts:
| Country | Guideline | In grams |
|---|---|---|
| Australia | no more than 10 standard drinks a week, and no more than 4 on any one day | 100 g a week |
| UK | no more than 14 units a week, spread over three or more days | 112 g a week |
| Sweden | 10 standardglas a week, or 4 on one occasion, is where risky drinking starts | 120 g a week |
| Canada | 2 standard drinks or fewer a week is low risk | 27 g a week |
None of these is a safe amount, and some have come down sharply: Canada cut its guidance from 10–15 drinks a week to 2 in 2023. Each of them says the same thing underneath: the less you drink, the lower the risk.
Standard drinks and blood alcohol
A count of standard drinks is the starting point for estimating your blood alcohol, but it is not the answer. The same 40 g puts a 60 kg woman at a much higher level than a 90 kg man, and the level then falls by roughly 0.10–0.15 per mille an hour, whatever you do.
The BAC calculator on this blog turns a number of standard drinks into an estimated level, and shows how long the alcohol is expected to stay in your body. The drink-driving limits by country show where the legal line sits, and the guide to driving the day after explains why a big night can still show up the next morning.
What no number of drinks can tell you is whether you are fit to drive. Limits are measured in your blood or breath, not in glasses, and the only safe count before driving is zero.
Frequently asked questions
How much pure alcohol is in one standard drink?
How many standard drinks are in a bottle of wine?
Is one beer one standard drink?
How many UK units is a standard drink?
How many standard drinks can I have and still drive?
How long does it take the body to clear one standard drink?
Count your drinks with Mypromille
Mypromille does the arithmetic above for you: log what you drink, by volume and strength, and the app keeps a running total of the alcohol and an estimate of your blood alcohol level.
The app is available for iPhone, Android and straight in the browser.
Sources: NIAAA — What is a standard drink? for the USA; NHS — Calculating alcohol units for the UK; the Australian Government’s standard drinks guide and NHMRC alcohol guidelines for Australia; the CCSA’s Canada’s Guidance on Alcohol and Health for Canada; Systembolaget and Kunskapsguiden for Sweden; Kalinowski and Humphreys, Governmental standard drink definitions and low-risk alcohol consumption guidelines in 37 countries (Addiction, 2016) for the other countries. Checked September 2026.