Basics
What is a standard drink? Sizes by country, with real examples
A “drink” on a guideline is not a glass, a can or a pour. It is a fixed amount of pure alcohol — and that amount changes depending on which country wrote the guideline.
What a standard drink actually measures
Health guidelines count alcohol in standard drinks (or units in the UK). A standard drink is a set amount of pure ethanol, measured in grams. A small glass of strong wine and a big can of light beer can contain exactly the same amount — or very different amounts — even though both feel like “one drink”.
That matters because the body responds to the alcohol, not to the glass. If you count glasses instead of alcohol, a heavy pour or a strong craft beer quietly turns one drink into two.
Standard drink sizes by country
There is no global standard. The most common size is 10 grams of alcohol, which the World Health Organization also uses in its AUDIT screening questionnaire, but the US and Canada use larger drinks and the UK uses a smaller unit.
| Country | Name | Pure alcohol | Low-risk guidance |
|---|---|---|---|
| United States | Standard drink | 14 g | NIAAA describes low-risk drinking as no more than 4 drinks on any day and 14 a week for men, and no more than 3 a day and 7 a week for women. |
| United Kingdom | Unit | 8 g | No more than 14 units a week on a regular basis, spread over three or more days. |
| Australia | Standard drink | 10 g | No more than 10 standard drinks a week and no more than 4 on any one day. |
| Canada | Standard drink | 13.45 g | 2 or fewer drinks a week is low risk; 3–6 is moderate risk; 7 or more is increasingly high risk. |
| Ireland | Standard drink | 10 g | Under 11 standard drinks a week for women and 17 for men, with 2–3 alcohol-free days and no more than 6 on one occasion. |
The US is a special case: the 2025–2030 Dietary Guidelines for Americans, published in January 2026, dropped the old “up to 2 drinks a day for men, 1 for women” numbers and now simply advise people to drink less for better overall health.
Because the sizes differ, “two drinks” in Canada (about 27 g) is more alcohol than “two units” in the UK (16 g). When you compare advice from different countries, compare grams.
How many standard drinks are in common drinks
These numbers are calculated from the volume and strength (ABV) of each drink. Your actual drink may differ — check the label, because craft beers and wines are often stronger than the “typical” values.
| Drink | Size | ABV | Alcohol | US drinks | UK units | 10 g drinks |
|---|---|---|---|---|---|---|
| Can of beer | 12 oz / 355 ml | 5% | 14.0 g | 1.0 | 1.8 | 1.4 |
| Pint of beer (US) | 16 oz / 473 ml | 5% | 18.7 g | 1.3 | 2.4 | 1.9 |
| Pint of beer (UK) | 568 ml | 5% | 22.4 g | 1.6 | 2.8 | 2.2 |
| Craft IPA | 16 oz / 473 ml | 7% | 26.1 g | 1.9 | 3.3 | 2.6 |
| Hard seltzer | 12 oz / 355 ml | 5% | 14.0 g | 1.0 | 1.8 | 1.4 |
| Glass of wine (US pour) | 5 oz / 148 ml | 12% | 14.0 g | 1.0 | 1.8 | 1.4 |
| Medium glass of wine | 175 ml | 13% | 17.9 g | 1.3 | 2.3 | 1.8 |
| Large glass of wine | 250 ml | 13% | 25.6 g | 1.8 | 3.3 | 2.6 |
| Bottle of wine | 750 ml | 13% | 76.9 g | 5.5 | 9.8 | 7.7 |
| Shot of spirits (US) | 1.5 oz / 44 ml | 40% | 13.9 g | 1.0 | 1.8 | 1.4 |
| Single spirit (UK) | 25 ml | 40% | 7.9 g | 0.6 | 1.0 | 0.8 |
| Double spirit (UK) | 50 ml | 40% | 15.8 g | 1.1 | 2.0 | 1.6 |
Two things usually surprise people: a large glass of wine is close to two US drinks, and a bottle of wine shared between two people is almost three drinks each.
Check any drink in the standard drink calculator: grams of alcohol, US drinks and UK units in one place.
How to work it out yourself
You only need the volume and the ABV printed on the label:
- Grams of alcohol = volume in ml × ABV% ÷ 100 × 0.789 (the density of ethanol).
- UK units = volume in ml × ABV% ÷ 1000.
- Standard drinks = grams of alcohol ÷ your country’s standard (14 for the US, 10 for Australia, Ireland and New Zealand, 13.45 for Canada).
Example: a 500 ml can of 6% beer contains 500 × 6 ÷ 100 × 0.789 = 23.7 g of alcohol. That is 1.7 US drinks, 3 UK units or 2.4 Australian standard drinks.
What this means when you track your drinking
For day-to-day tracking, perfect precision matters less than consistency. Pick one rule and stick with it:
- If you mostly drink standard cans, shots or small glasses, count each as one drink.
- If you drink pints, large glasses or strong craft beer, count each as two.
- If you pour at home, measure your usual glass once, so you know what “a glass” really means for you.
The point is to see the pattern over weeks — how many days you drink, how much on a typical day and where the heavier days cluster. A consistent count shows that clearly, even if each number is slightly rounded.
Frequently asked questions
How many grams of alcohol are in a standard drink?
It depends on the country: 14 g in the United States, 13.45 g in Canada, 10 g in Australia, Ireland and New Zealand, and 8 g in a UK unit.
Is a glass of wine one standard drink?
Only a small one. A 5 oz (148 ml) glass of 12% wine is one US standard drink, but a 250 ml glass of 13% wine is about 1.8 US drinks or 3.3 UK units.
Is a pint of beer one drink?
Usually not. A UK pint of 5% beer has about 22 g of alcohol: 1.6 US standard drinks or 2.8 UK units.
What is the difference between a unit and a standard drink?
A UK unit is 8 g (10 ml) of pure alcohol. Most standard drinks are larger, so one standard drink is usually more than one unit.
Sources
- NIAAA — What is a standard drink?
- NIAAA — Rethinking Drinking: what counts as a drink and low-risk drinking levels
- NHS — Alcohol units
- NHMRC — Australian guidelines to reduce health risks from drinking alcohol
- Health Canada — Canada’s Guidance on Alcohol and Health
- HSE — Weekly low-risk alcohol guidelines
- Dietary Guidelines for Americans 2025–2030
This article is general information, not medical advice. See our disclaimer and help resources.