What is the Alcohol Unit Calculator?
This tool uses the UK definition of an alcohol unit, where one unit equals 10 millilitres (8 grams) of pure alcohol. By entering the volume of your drink in millilitres and its strength as an ABV percentage, you can see exactly how many units it contains and how many you consume across several drinks. It is useful for staying within the UK Chief Medical Officers' low-risk guideline of no more than 14 units per week.
How to use it
Enter the volume in ml (for example a pint is 568 ml, a small glass of wine is 175 ml, a standard spirit measure is 25 ml), the ABV (%) printed on the label, and the number of drinks. The calculator returns the units in a single drink and the total for all of them.
The formula explained
The calculation is $$\text{Units} = \dfrac{\text{Volume (ml)} \times \text{ABV (\%)}}{1000}$$ The division by 1000 converts the result so that 10 ml of pure alcohol equals exactly one unit. Multiplying by the number of drinks gives your total intake.
Worked example
A pint (568 ml) of beer at 4.5% ABV: $$568 \times 4.5 \div 1000 = \textbf{2.556 units}$$ Two pints would be \(5.112\) units — over a third of the weekly low-risk limit in a single sitting.
Units in Common UK Drinks
In the UK, one alcohol unit is defined as 10ml (8g) of pure alcohol. The number of units in any drink is found with:
$$\text{Units} = \frac{\text{Volume (ml)} \times \text{ABV (\%)}}{1000}$$For example, a pint of 4% lager contains \(\frac{568 \times 4}{1000} = \) 2.27 units. The table below shows units for typical UK servings (a UK pint is 568ml).
| Drink | Volume (ml) | ABV (%) | Units |
|---|---|---|---|
| Pint of standard lager | 568 | 4.0 | 2.3 |
| Pint of strong lager | 568 | 5.2 | 3.0 |
| Small glass of wine | 125 | 13.0 | 1.6 |
| Standard glass of wine | 175 | 13.0 | 2.3 |
| Large glass of wine | 250 | 13.0 | 3.3 |
| Single spirit measure | 25 | 40.0 | 1.0 |
| Alcopop / pre-mixed bottle | 275 | 5.0 | 1.4 |
Interpreting Your Weekly Units
The UK Chief Medical Officers' (CMO) low-risk drinking guideline advises that, to keep health risks from alcohol low, both men and women should drink no more than 14 units per week on a regular basis. There is no level of regular drinking that is completely free of risk, but staying within 14 units keeps the risk of harm low for most adults.
- Within 14 units/week: You are within the low-risk guideline. This is roughly equivalent to about 6 pints of average-strength lager or 6 medium (175ml) glasses of wine across a whole week.
- Above 14 units/week: The risk of long-term health conditions — including liver disease, several cancers and high blood pressure — increases as weekly intake rises above the guideline.
The CMO guidance also recommends that if you do drink as much as 14 units a week, you should spread it evenly over three or more days rather than concentrating it into one or two heavy sessions, since drinking a lot in a short time ("binge" drinking) raises the risk of accidents and injury. Having several drink-free days each week is a good way to cut down and reduce overall intake.
The 14-unit guideline applies to regular weekly drinking and is the same for men and women. Pregnant women are advised that the safest approach is not to drink alcohol at all.
This is general information based on UK CMO guidance and is not personal medical advice. If you are concerned about your drinking, speak to a healthcare professional.
FAQ
Is this UK-specific? Yes. A UK unit is 10 ml of pure alcohol. The US "standard drink" is larger (14 g), so US figures will differ.
What is the weekly guideline? UK guidance recommends no more than 14 units per week for both men and women, spread over several days.
How many units is a glass of wine? A 175 ml glass at 13% ABV is $$175 \times 13 \div 1000 = 2.275 \text{ units}$$
