In the UK, one alcohol unit is 10 ml of pure alcohol. You can work out the units in any drink with one formula: volume in millilitres times the strength (ABV, in per cent), divided by 1,000. The UK Chief Medical Officers advise that adults keep to no more than 14 units a week, spread over three or more days.
What is a unit of alcohol?
A unit measures the amount of pure alcohol in a drink, not the amount of liquid. That is why a small glass of strong wine can hold more alcohol than a larger glass of light beer. One unit is 10 ml of pure alcohol, which weighs about 8 grams.
The strength on a label is the ABV, or alcohol by volume. A 12% wine is 12% pure alcohol by volume.
The formula
units = volume in ml × ABV% ÷ 1000
For example, a pint is 568 ml. At 4% ABV that is 568 × 4 ÷ 1000 = 2.27 units. At 5% it is 2.84 units. Multiply by the number of drinks to get the total.
How many units are in common drinks?
These figures use common UK serving sizes and typical strengths. Check the label for the real strength.
| Drink | Typical size and strength | Units |
|---|---|---|
| Pint of beer or lager | 568 ml at 4% | 2.3 |
| Pint of strong lager | 568 ml at 5% | 2.8 |
| Pint of cider | 568 ml at 4.5% | 2.6 |
| Can of beer | 440 ml at 4.5% | 2.0 |
| Small glass of wine | 125 ml at 12% | 1.5 |
| Standard glass of wine | 175 ml at 12% | 2.1 |
| Large glass of wine | 250 ml at 12% | 3.0 |
| Single spirit measure | 25 ml at 40% | 1.0 |
| Bottle of wine | 750 ml at 12.5% | 9.4 |
Strength varies a lot. Many wines are stronger than 12%, craft beers can be well above 5%, and pub measures and home pours are often bigger than the standard sizes, so real units are frequently higher than the table suggests.
What the UK guideline says
The UK Chief Medical Officers’ low-risk guideline is no more than 14 units a week for both men and women. The advice is also to spread this over three or more days rather than drinking it all at once, and to have several alcohol-free days. It is a limit for lower-risk drinking, not a target, and there is no completely risk-free level. If you are pregnant or trying to conceive, the advice is not to drink. This guidance has been stable for some years, but check the NHS for the latest.
For a sense of scale, 14 units is roughly 5.5 pints of 4.5% cider or about 6.7 standard 175 ml glasses of 12% wine.
A worked example
Suppose you have two pints of 4% beer and one standard glass of wine on each of two evenings a week. The calculator gives:
- Two pints at 4%: 4.5 units
- One 175 ml glass at 12%: 2.1 units
- Total per evening: 6.6 units
- Across two evenings a week: 13.3 units, about 95% of the 14-unit guideline
The alcohol alone in that evening is about 66 ml of pure alcohol, which is roughly 367 calories at 7 calories per gram. Mixers, sugar and bar snacks come on top, so the real total is higher. The guide to Calories and TDEE: how many calories do you need? shows how that fits into a day’s energy needs.
Tips for keeping count
- Check the ABV on the label, not just the drink type.
- Count the real pour: a large glass or a double adds up quickly.
- Plan alcohol-free days, and spread drinks across the week.
- Alternate with water. How much water should you drink each day? explains general hydration advice.
- Note that units say nothing about whether you are safe to drive. Do not use any unit count to judge that; the safest advice is not to drink if you are driving.
Note: This is general information, not medical advice. If you are worried about your drinking, or someone else’s, speak to a GP or use NHS services for support.
Try the calculator
Choose your drinks in the Alcohol units calculator calculator, edit the volume or strength, and see your total units and how they compare with the weekly guideline. You can add up to four different drinks.
Open the free Alcohol units calculator
Step-by-step: how to count units by hand
You do not need a calculator for a rough count, only the label and a phone. Work through these steps for each drink.
- Find the strength (ABV) on the label or menu. If it says 13.5% vol, use 13.5.
- Find the volume in millilitres. A pint is 568 ml, a half pint 284 ml, a standard can often 330 ml or 440 ml, a bottle of wine 750 ml.
- Multiply volume by ABV, then divide by 1,000.
- Multiply by the number of identical drinks.
- Add up every drink across the days you drink, then compare the weekly total with the 14-unit guideline.
A quick shortcut: the ABV figure is roughly the units in a litre. A litre of 5% beer is 5 units, so half a litre is 2.5. A 750 ml bottle at 13% is 750 × 13 ÷ 1,000 = 9.75, which rounds to 9.8 units.
Worked example 2: a weekend and a mid-week drink
Imagine three evenings a week with two 250 ml glasses of 13% wine and one pint of 5% lager. Using the House of Calculator alcohol units calculator:
| Item | Working | Units |
|---|---|---|
| Two 250 ml glasses at 13% | 2 × 250 × 13 ÷ 1,000 | 6.5 |
| One pint (568 ml) at 5% | 568 × 5 ÷ 1,000 | 2.8 |
| Per evening | 9.3 | |
| Per week (three evenings) | 9.3 × 3 | 28 |
That is about 200% of the 14-unit weekly guideline, and the pure alcohol in one evening is roughly 93 ml, or about 516 calories from the alcohol alone. Nothing here is unusual: large 250 ml glasses are common in bars and restaurants, which is exactly why people underestimate what they drink.
Now compare a single heavier evening. A 750 ml bottle of 13% wine (9.8 units) plus four 330 ml bottles of 5% beer (6.6 units) comes to 16.4 units in one session. That is above the weekly guideline in a single night, even though the weekly count looks like “only one night out”. The guideline’s advice to spread drinking over three or more days exists for this reason.
Common mistakes when counting units
- Counting drinks, not units. “Two drinks” can be 2 units or 6, depending on size and strength.
- Trusting the drink type. Lager is not always 4%, and wine is often 13% or 14% rather than 12%. Use the label.
- Forgetting home pours. A generous glass poured at home is often well over 175 ml. Measure once with a jug and you will know your real glass size.
- Ignoring mixers. Units cover only the alcohol. Cocktails and long drinks may contain several measures of spirit, plus sugar.
- Averaging a heavy night across the week. The weekly figure matters, but so does the pattern. Several units on one night is different from the same units spread out.
- Rounding every drink down. Rounding 2.8 down to 2 each time can hide a large error by Sunday.
Units, calories and strength
Alcohol itself provides 7 kcal per gram, which is more than carbohydrate or protein (4 kcal) and less than fat (9 kcal). One unit is about 8 g of pure alcohol, so a unit carries roughly 56 kcal before any sugar or mixer is added. A single 568 ml pint of 5% lager is 2.8 units, or about 160 kcal from alcohol alone, and real beers usually contain carbohydrate on top.
If you are tracking energy, the guide to Calories and TDEE: how many calories do you need? explains how to estimate your daily needs, and BMI explained: what it tells you and what it doesn't covers one common screening measure. Alcohol also contributes to dehydration for some people, so the general advice in How much water should you drink each day? is a useful companion.
Glossary of terms
- ABV: alcohol by volume, the percentage of the liquid that is pure alcohol. Sometimes printed as “vol”.
- Unit: 10 ml, or about 8 g, of pure alcohol.
- Pure alcohol: the ethanol content of a drink, as opposed to the total volume of liquid.
- Measure: the standard pour for a drink, such as a 25 ml or 35 ml spirit measure or a 125, 175 or 250 ml glass of wine.
- Low-risk guideline: the UK Chief Medical Officers’ advice of no more than 14 units a week, spread over three or more days. Lower risk does not mean no risk.
When to speak to a professional
If you regularly drink more than the guideline, find it hard to cut down, or notice withdrawal symptoms when you stop, speak to a GP before stopping suddenly, because that can be dangerous for some people. The NHS website lists local support services, and you can ask a GP or pharmacist about alcohol and any medicines you take.
Frequently asked questions
How many units are in a bottle of wine?
A 750 ml bottle at 12% ABV contains 9 units, and a 13% bottle has about 9.8. The exact figure depends on the strength printed on the label.
Is 14 units a lot?
It is the upper limit of the UK low-risk guideline, not a recommended amount. Drinking less carries lower risk, and spreading drinks over several days is advised.
Do units depend on the size of the person?
No. Units measure the alcohol in the drink. How strongly alcohol affects someone does depend on things like body size, food and medicines, but the unit count does not change.
Why do pub measures differ from the guidance?
Many venues serve 175 ml or 250 ml glasses of wine, and spirits may be 25 ml or 35 ml measures in some places. Ask for the size or check the menu so you can count units properly.
How many units are in a 330 ml bottle of beer?
At 5% ABV, a 330 ml bottle contains 330 × 5 ÷ 1,000 = 1.65 units. At 4% it is 1.3 units. Use the printed strength for your brand.
How many calories are in a unit of alcohol?
About 56 kcal from the alcohol itself (8 g at 7 kcal per gram). Sugar, mixers and carbohydrate in the drink add more.
Does a half pint count as half the units?
Yes, if the strength is the same. A half pint (284 ml) of 4% beer is about 1.1 units, half of the 2.3 units in a full pint.
Does the 14-unit guideline mean 14 units is safe?
No. It is a low-risk limit, not a safe level, and drinking less carries lower risk. Check the NHS for the latest advice.