Alcohol Units Calculator
Calculate the number of alcohol units and calories in your drinks. See your risk level based on UK CMO guidelines and find out how long it takes to clear alcohol from your system.
Within UK CMO low-risk guidelines of 14 units per week spread over 3+ days.
How to Use Alcohol Units Calculator
- Use the + and - buttons to adjust quantities for the default drinks shown.
- Click any drink in the "Add a drink" section to add it to your list.
- For custom drinks, enter the name, ABV percentage, and volume in ml, then click Add drink.
- Total units, calories, and your risk level update instantly.
What is a UK Alcohol Unit?
One UK unit of alcohol is defined as 10 ml (8 grams) of pure ethanol. The number of units in any drink is calculated with a simple formula: ABV (%) multiplied by volume (ml) divided by 1,000. For example, a 330 ml bottle of beer at 5% ABV contains 330 × 5 / 1,000 = 1.65 units. The unit system was introduced in the UK in 1987 to help people understand how much alcohol they are consuming in practical terms.
Units make it easier to compare drinks with very different volumes and strengths. A single shot of 40% spirits (25 ml) contains exactly 1 unit, while a pint of 4% beer contains 2.3 units. Without the unit framework, it is easy to underestimate consumption when switching between drink types.
UK CMO Guidelines (2016)
The UK Chief Medical Officers updated the low-risk drinking guidelines in 2016. The key recommendations are: drink no more than 14 units per week; if you do drink 14 units, spread them across 3 or more days rather than having them in one or two sessions; and have several alcohol-free days each week. The 14-unit limit now applies equally to men and women, replacing the previous higher limit for men of 21 units.
The guidelines make clear there is no completely safe level of alcohol consumption. Drinking within these limits reduces (but does not eliminate) risks of cancer, liver disease, heart conditions, and accidents. The CMO guidance is about setting a level where risks are considered low rather than zero.
Alcohol and Calories
Alcohol contains approximately 7 kcal per gram (compared to 4 kcal/g for protein or carbohydrate, and 9 kcal/g for fat). Since one unit contains 8 grams of alcohol, each unit contributes roughly 56 kcal from the alcohol itself. This means a bottle of wine (around 10 units) contributes around 560 kcal from alcohol alone, before accounting for any sugars or mixers. Alcohol calories are often called "empty calories" because they provide no nutritional value.
Track your overall daily calorie needs with the Calorie Calculator, or check your health metrics with the BMI Calculator.