What is the Alcohol Units Calculator?
This calculator uses the UK standard definition of an alcohol unit, as used by the NHS. One UK unit equals 10 ml (8 grams) of pure alcohol. It tells you how many units are in a drink given its volume in millilitres and its alcohol by volume (ABV) percentage, so you can keep track against the UK Chief Medical Officers' guideline of no more than 14 units per week. Note: unit definitions differ by country (the US uses 14 g "standard drinks"), so this tool applies to UK guidance.
How to use it
Enter the volume of one drink in millilitres (a pint is 568 ml, a large wine glass is 250 ml, a single spirit measure is 25 ml). Enter the ABV shown on the label as a percentage. Set the number of drinks if you want a session total. The calculator returns units per drink and the combined total.
The formula explained
The unit count comes from $$\text{Units} = \dfrac{\text{Volume (ml)} \times \text{ABV (\%)}}{1000}$$ The division by 1000 converts the percentage-millilitre product into the 10 ml-of-pure-alcohol unit scale. For example, the volume of pure alcohol in ml is \(\text{volume} \times \text{ABV} \div 100\), and dividing that by 10 (ml per unit) gives the same result.
Worked example
A large 250 ml glass of wine at 13% ABV: $$250 \times 13 \div 1000 = \textbf{3.25 units}$$ Drink two of them and that's 6.5 units in one sitting — almost half the weekly guideline.
Units in Common Drinks
UK alcohol units are calculated with the official NHS formula \[\text{Units} = \frac{\text{Volume (ml)} \times \text{ABV (\%)}}{1000}.\] One unit equals 10ml (8g) of pure alcohol. The table below shows typical servings and how many units each contains. Because units depend on both serving size and strength, a stronger or larger drink can hold far more than a single unit.
| Drink | Volume | ABV | Units |
|---|---|---|---|
| Single small measure of spirits (gin, vodka, whisky) | 25 ml | 40% | 1.0 |
| Double measure of spirits | 50 ml | 40% | 2.0 |
| Small glass of wine | 125 ml | 12% | 1.5 |
| Standard glass of wine | 175 ml | 13% | 2.3 |
| Large glass of wine | 250 ml | 14% | 3.5 |
| Alcopop (e.g. flavoured bottle) | 275 ml | 5% | 1.4 |
| Pint of lower-strength lager / beer / cider | 568 ml | 4% | 2.3 |
| Pint of higher-strength lager / beer / cider | 568 ml | 5.2% | 3.0 |
| Can of cider | 440 ml | 4.5% | 2.0 |
| Bottle of wine | 750 ml | 13.5% | 10.1 |
Worked example: a standard 175ml glass of 13% wine gives \[\frac{175 \times 13}{1000} = 2.275 \approx 2.3\text{ units}.\] A 568ml pint of 5.2% beer gives \(\frac{568 \times 5.2}{1000} \approx 3.0\) units, so two pints already account for about 6 units.
Interpreting Your Units
The UK Chief Medical Officers' (CMO) low-risk drinking guidelines advise that, to keep health risks from alcohol low, both men and women should drink no more than 14 units a week on a regular basis. This is equivalent to about 6 pints of average-strength beer or 6 standard 175ml glasses of wine across a week.
The guidelines make several points worth understanding when reading your total:
- Spread it out. If you regularly drink as much as 14 units a week, it is best to spread this evenly over three or more days. Concentrating your weekly units into one or two heavy sessions raises the risk of accidents, injury and longer-term harm.
- Have drink-free days. Building in several alcohol-free days each week is one way to cut down and to reduce the amount you drink overall.
- No completely safe level. The CMO guidance is explicit that there is no level of regular drinking that can be considered completely safe — 14 units is a threshold below which the risk of harm is low, not zero. The risk of developing a range of illnesses, including some cancers, increases the more you drink.
Session total versus weekly total. A session total is the units in a single occasion — useful for judging short-term effects such as intoxication. A weekly total is the sum across all your drinking days over seven days and is what the 14-unit guideline refers to. For example, three pints of 5.2% beer in one evening is roughly 9 units in a single session, which alone is most of the weekly low-risk amount. Tracking both helps you see whether a heavy session has pushed your week over the guideline.
This is general information based on the UK CMO low-risk drinking guidelines and NHS guidance. It is not medical advice. If you are concerned about your drinking or your health, speak to a GP or a qualified health professional.
FAQ
How many units is a pint of beer? A pint (568 ml) of 4% beer is \(568 \times 4 \div 1000 = 2.27\) units; a 5% pint is about 2.84 units.
What is the weekly limit? UK guidance recommends not regularly drinking more than 14 units a week, spread over three or more days.
How long to clear one unit? The body processes roughly one unit per hour, though this varies by person.
