Standard Drink Calculator
Convert any drink to grams of alcohol, US standard drinks and UK units.
Your drink
Alcohol content
A “drink” is not a fixed amount anywhere
Standard measures differ by country, which makes international guidance genuinely confusing. AUS standard drink is 14 grams of pure alcohol; a UK unit is 8 grams— roughly 10 ml. So the same pint of 5% beer is about 1.6 US standard drinks and 2.8 UK units. Neither figure is wrong; they are different scales.
The arithmetic is volume × ABV × 0.789, since ethanol weighs 0.789 g per millilitre. What catches people out is that a "drink" in everyday speech bears little relation to either standard. A large restaurant glass of wine at 250 ml and 13% is over three UK units in a single glass, and a strong craft beer at 7% in a 568 ml pint is nearly four. Counting glasses substantially understates intake.
UK guidance is no more than 14 units a week for both men and women, spread over three or more days, with several drink-free days. US guidance is up to two standard drinks a day for men and one for women. Both are framed as ceilings for lower-risk drinking rather than targets, and current evidence does not support any level as actively beneficial.
Medical disclaimer. This calculator is for general information and education only. It is not medical advice, not a diagnosis, and not a substitute for professional care. Alcohol guidance does not apply during pregnancy, where no level is considered safe, and it interacts with many medications and liver conditions.Speak to a doctor or another qualified clinician about any health decision.Last reviewed .
Frequently asked questions
What is a standard drink?
It depends on the country. A US standard drink contains 14 grams of pure alcohol; a UK unit contains 8 grams, or about 10 ml. Australia uses 10 grams. The same physical drink therefore converts to different numbers depending on which system you use.
How many units is a pint of beer?
A 568 ml pint at 5% ABV is about 2.8 UK units, or roughly 1.6 US standard drinks. A stronger craft beer at 7% pushes the same pint close to four units.
How many units are in a glass of wine?
A large 250 ml glass at 13% is around 3.3 UK units — nearly a quarter of the weekly guideline in one glass. A small 125 ml glass is about 1.6 units.
What are the weekly limits?
UK guidance is no more than 14 units a week for everyone, spread across three or more days with several drink-free days. US guidance is up to two standard drinks daily for men and one for women. Both are ceilings for lower-risk drinking, not targets.
Why 0.789 in the calculation?
That is the density of ethanol in grams per millilitre. Multiplying volume by ABV gives millilitres of pure alcohol, and multiplying by 0.789 converts that to grams, which is what the standards are defined in.