Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Standard Drinks Are Calculated
A standard drink is a set amount of pure alcohol. It lets you compare a beer, a glass of wine and a shot on one scale, whatever their size or strength. The calculator works out how much pure alcohol your drink holds, then divides it by the size of one standard drink.
What a Standard Drink Measures
A standard drink counts pure alcohol (ethanol) only. In the US, it is about 14 grams, or 0.6 fl oz, of pure alcohol: the amount in 12 fl oz of regular beer at about 5%, 5 fl oz of table wine at about 12%, or a 1.5 fl oz shot of 40% spirits¹. It does not measure calories or blood alcohol. For those, use the Alcohol Calorie Calculator or the Blood Alcohol Content Calculator.
The Formula
Pure alcohol (mL) = volume per drink (mL) x (ABV / 100) x number of drinks
Grams of alcohol = pure alcohol (mL) x 0.789
Standard drinks = grams of alcohol / grams in one standard drink
UK units = pure alcohol (mL) / 10
ABV means alcohol by volume, the percent on the label. The factor 0.789 turns milliliters of ethanol into grams, because ethanol weighs 0.789 g per mL at 20°C (0.7893, rounded)². A UK unit is 10 mL or 8 g of pure alcohol, and the NHS counts units by volume, as ABV x mL / 1,000³.
How This Calculator Computes Your Result
Pick a standard: United States (14 g)¹, Canada (13.45 g, or 17.05 mL)⁴, United Kingdom (1 unit = 10 mL)³, Australia (10 g)⁵ or the WHO reference (10 g)⁶. Choose one of its official example drinks or Custom, then enter the volume of one drink (US fl oz or mL), the ABV and the number of drinks. Fluid ounces are converted at 29.5735295625 mL, the exact US fluid ounce. You get standard drinks to one decimal place, the grams and milliliters of pure alcohol, the same total in the other four standards, and the official guidance for your chosen standard.
What Your Result Means
A result of 1.0 means your drinks hold one standard drink of pure alcohol, to one decimal place. Here is the size of one standard drink and the current official guidance for each option.
Standard | One standard drink | Current official guidance |
United States | 14 g¹ | Dietary Guidelines for Americans 2025-2030: "Consume less alcohol for better overall health." No daily or weekly number is given⁷. |
Canada | 13.45 g (17.05 mL)⁴ | 2 or fewer a week is low risk, 3 to 6 is moderate, 7 or more is increasingly high. More than 2 on one occasion is linked with a higher risk of harms⁴. |
United Kingdom | 1 unit = 10 mL or 8 g³ | Not more than 14 units a week on a regular basis, spread over 3 or more days⁸. |
Australia | 10 g⁵ | No more than 10 a week and no more than 4 on any one day⁵. |
WHO reference | 10 g⁶ | The size used in the WHO AUDIT screening test. A reference amount, not a limit⁶. |
The US guidelines say pregnant women, people recovering from alcohol use disorder or unable to control their drinking, and people taking medicines or with conditions that interact with alcohol should avoid alcohol completely⁷. In pregnancy, UK and Australian guidance say not to drink, and Canada's says there is no known safe amount⁴ ⁵ ⁸.
The Same Drink in Five Standards
Countries define a standard drink differently, partly because typical serving sizes differ⁶. Among 37 countries with an official definition, the most common size was 10 g of pure alcohol, but the range was 8 g to 20 g⁹. So one drink can give several counts:
Drink | US | Canada | UK units | Australia | WHO |
Beer, 12 fl oz at 5% | 1.0 | 1.0 | 1.8 | 1.4 | 1.4 |
Wine, 175 mL at 12% | 1.2 | 1.2 | 2.1 | 1.7 | 1.7 |
Beer, UK pint (568 mL) at 5.2% | 1.7 | 1.7 | 3.0 | 2.3 | 2.3 |
Wine, 750 mL bottle at 13.5% | 5.7 | 5.9 | 10.1 | 8.0 | 8.0 |
The NHS lists the same glass and pint at 2.1 and 3 units, and rounds the bottle to 10³. Use the standard of the country whose label or guideline you are reading.
Why Real Drinks Often Hold More Than One
NIAAA notes that standard amounts may not match the servings people actually drink, and that alcohol content varies within each type of drink. A 12 fl oz beer at 10% ABV holds two US standard drinks¹. In a study of drinks bought at 80 bars and restaurants in Northern California, the average glass of wine held 43% more alcohol than a US standard drink, mixed drinks 42% more and draft beer 22% more. Shots matched one standard drink¹⁰. Typing proof instead of ABV is another common mistake. US 80-proof spirits are about 40% alcohol¹, so enter 40, not 80.
Pure Alcohol in One Standard Drink by Standard
Grams of pure alcohol in one standard drink under each of the five standards this calculator offers.
- Pure alcohol in one standard drink
Show data table
| Standard | Pure alcohol in one standard drink |
|---|---|
| United States | 14 g |
| Canada | 13.45 g (17.05 mL) |
| Australia | 10 g |
| WHO reference | 10 g |
| United Kingdom (1 unit) | 10 mL or 8 g |
The Same Drink Counted in Five Standards
Standard drinks (UK units for the UK) in four common drinks. Pick a drink and a standard to compare.
- Under 1.5
- 1.5–2.4
- 2.5–4.9
- 5.0–7.9
- 8.0 and above
| Drink | Standard | ||||
|---|---|---|---|---|---|
| US | Canada | UK units | Australia | WHO | |
| Beer, 12 fl oz, 5% | 1.0 | 1.0 | 1.8 | 1.4 | 1.4 |
| Wine, 175 mL, 12% | 1.2 | 1.2 | 2.1 | 1.7 | 1.7 |
| UK pint of beer (568 mL), 5.2% | 1.7 | 1.7 | 3.0 | 2.3 | 2.3 |
| Bottle of wine (750 mL), 13.5% | 5.7 | 5.9 | 10.1 | 8.0 | 8.0 |
Use the arrow keys to move between cells.
A Note on Accuracy
The math is exact for the numbers you enter, so the result is only as good as your volume and ABV. Measure the pour if you can and read the ABV from the label, since drinks of the same type vary¹. A standard drink count measures the alcohol in the glass, not its effect on your body. It is not a blood alcohol estimate and cannot tell you whether it is safe to drive.
Frequently Asked Questions
What counts as one standard drink?
In the US, one standard drink has about 14 grams of pure alcohol, the amount in 12 fl oz of beer at 5%, 5 fl oz of wine at 12%, or 1.5 fl oz of 40% spirits¹. Canada uses 13.45 g and Australia 10 g⁴ ⁵.
How many standard drinks are in a bottle of wine?
A 750 mL bottle at 12% ABV holds about 5.1 US standard drinks, and at 13.5% about 5.7. In UK units, a 750 mL bottle at 13.5% is about 10 units³.
How many standard drinks a week is low risk?
It depends on the country: the UK guideline is not more than 14 units a week⁸, Australia's is no more than 10 standard drinks a week and 4 on any one day⁵, and Canada's guidance calls 2 or fewer a week low risk⁴. The current US Dietary Guidelines give no number and say to consume less alcohol for better overall health⁷.
How accurate is this standard drink calculator?
The arithmetic is exact and matches the NHS unit formula³. Most errors come from the inputs, because real pours are often larger than a standard serving, especially wine and mixed drinks in bars¹⁰.
Sources
What Is a Standard Drink?, National Institute on Alcohol Abuse and Alcoholism
Ethanol (Compound Summary), PubChem, National Library of Medicine
Alcohol Units, NHS
Canada's Guidance on Alcohol and Health: Final Report, Canadian Centre on Substance Use and Addiction, 2023
How Much Alcohol Is Safe to Drink?, Australian Government
AUDIT: Guidelines for Use in Primary Care, Babor et al., World Health Organization, 2001
Dietary Guidelines for Americans, 2025-2030, US Department of Agriculture and US Department of Health and Human Services, 2026
UK Chief Medical Officers' Low Risk Drinking Guidelines, UK Chief Medical Officers, 2016
Governmental Standard Drink Definitions and Low-Risk Alcohol Consumption Guidelines in 37 Countries, Kalinowski and Humphreys, 2016
Alcohol Content Variation of Bar and Restaurant Drinks in Northern California, Kerr et al., 2008