Alcohol Units Calculator
In the UK, alcohol is measured in units: one unit is 10 millilitres, or 8 grams, of pure alcohol. This calculator works out the units in a drink from its volume in millilitres and its ABV, then multiplies by the number of drinks for a session total. UK Chief Medical Officers advise keeping to no more than 14 units a week, spread across several days. Enter your drink size, the ABV from the label, and how many you have had to track your units against that guideline. The measure reflects the alcohol in the drink, not its effect on you.
Alcohol units formula
Units per drink = volume (ml) * ABV (%) / 1,000
Total units = units per drink * number of drinks
Pure alcohol (ml) = volume * ABV / 100 * number of drinks
Share of weekly guideline = total units / 14 * 100
One UK unit is 10 ml of pure alcohol. The weekly low-risk guideline is 14 units for both men and women.
Unit guidance
- UK guidance is no more than 14 units a week, spread over three or more days.
- Read the ABV from the label, as strengths vary widely within a drink type.
- Stronger beers, wines, and large measures contain more units than people expect.
- Having several drink-free days each week is recommended.
- UK units differ from US standard drinks; do not mix the two measures.
Alcohol units: frequently asked questions
How are alcohol units calculated?
In the UK, one unit is 10 millilitres (8 grams) of pure alcohol. Units equal the volume of the drink in millilitres multiplied by its ABV percentage, divided by 1,000. For example, a 568 ml pint at 4% ABV is 568 times 4 divided by 1,000, which is about 2.3 units.
What is ABV?
ABV stands for alcohol by volume, the percentage of a drink that is pure alcohol. It is printed on the label, for example 4% for many beers, 12% to 14% for wine, and 40% for many spirits. Enter the ABV exactly as shown on the container.
What are the UK low-risk drinking guidelines?
UK Chief Medical Officers advise both men and women to drink no more than 14 units per week on a regular basis, spread over three or more days rather than saved up. This calculator helps you count units so you can compare against that guideline.
Are UK units the same as US standard drinks?
No. A UK unit is 8 grams of pure alcohol, while a US standard drink is 14 grams. They are different measures, so do not mix them. Use our standard drink calculator for the US definition.
Does drinking the same units affect everyone equally?
No. Body size, sex, food intake, medication, and individual factors all affect how alcohol is processed. Units measure the alcohol in the drink, not its effect on a specific person. If you have health concerns, follow advice from a qualified professional.
Official sources
- UK National Health Service: Alcohol units.
- UK Government: Chief Medical Officers' low-risk drinking guidelines.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.