Alcohol Units Calculator
Count units and grams of alcohol in a drink.
Alcohol by volume, shown on the label.
Results update as you type.
This calculator provides estimates based on population research. Results are not medical advice. Consult a qualified healthcare provider before making health or nutrition decisions.
How it works
An alcohol units calculator translates any drink into a standard measure of how much pure alcohol it actually contains, cutting through the confusion of different glass sizes and strengths. In the UK, one unit is defined as 10 millilitres, or about 8 grams, of pure alcohol, the amount an average adult can process in roughly an hour. This tool computes units directly from a drink's volume and its alcohol by volume percentage, the ABV printed on every label, and also reports the grams of pure alcohol for those who prefer that measure or follow guidance from other countries. Understanding units matters because health guidance is written in them: the UK Chief Medical Officers advise drinking no more than 14 units per week for both men and women, spread across three or more days, with several alcohol-free days. It is remarkably easy to underestimate intake, since a large glass of strong wine or a craft beer in a big measure can contain three or more units on its own. An alcohol units calculator helps you keep an honest running tally, compare drinks fairly and stay within lower-risk limits. Regularly exceeding those limits raises the risk of liver disease, several cancers, high blood pressure and dependence. Use this tool to plan a night out, track a week's consumption, or simply understand a drink you are unfamiliar with, and remember that no level of drinking is completely risk-free.
UK units = volume(ml) × ABV(%) ÷ 1000; grams = volume × (ABV ÷ 100) × 0.789
The UK unit formula multiplies the drink's volume in millilitres by its ABV percentage and divides by 1,000, which follows directly from the definition that one unit is 10 millilitres of pure alcohol. To find the mass of alcohol, the volume of pure alcohol, volume times ABV over 100, is multiplied by 0.789, the density of ethanol in grams per millilitre, converting that liquid volume into grams for nutrition-style labelling and international comparisons.
Source:UK NHS / Chief Medical Officers' alcohol unit guidance
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter drink volume and abv.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Alcohol units updates instantly as you type — no button to press.
Frequently asked questions
What exactly is one unit of alcohol?
In the UK, one unit equals 10 millilitres or roughly 8 grams of pure alcohol, chosen because it is about the amount an average adult body clears in an hour. That translates to a single 25 ml measure of spirits at 40 percent, while a pint of strong beer or a large glass of wine can be three units or more. Units let you compare very different drinks on a common scale of actual alcohol content.
How many units are safe to drink?
UK Chief Medical Officers advise keeping to no more than 14 units per week for both men and women, spread evenly over three or more days rather than saved up, with some drink-free days. This level keeps health risks low but not zero. Regularly drinking above 14 units raises the risk of liver disease, several cancers and high blood pressure. Other countries set different limits, so check the guidance that applies to you.
Why does drink strength vary so much?
ABV, alcohol by volume, ranges widely: light beers sit near 3.5 percent, standard lagers around 5, strong craft beers 7 to 9, wines 11 to 14, fortified wines around 20, and spirits typically 40 percent. Because units depend on both volume and ABV, a small glass of a strong drink can carry more alcohol than a large glass of a weak one. Always check the label's ABV, as a stronger drink means more units in the same measure.
How long does it take to process the alcohol?
The body clears roughly one unit per hour on average, though this varies with sex, weight, food, liver health and genetics. So a drink containing three units takes about three hours to leave your system, and nothing reliably speeds this up, not coffee, water or a cold shower. This is why alcohol can linger the morning after heavy drinking, potentially leaving you over a driving limit long after your last drink.
Are grams or units the better measure?
They measure the same thing in different scales. The UK and Ireland use units, where one unit is 8 grams of alcohol, while many other countries and scientific studies use grams directly, and some define a standard drink as 10 or 14 grams. This calculator shows both so you can follow whichever guidance applies to you. Grams are more precise and internationally comparable; units are the everyday shorthand in British health advice.