Understanding alcohol units helps you track your drinking and stay within recommended limits. This guide explains how to calculate units and provides quick references for common drinks.
What is an Alcohol Unit?
One UK alcohol unit equals 10ml (or 8g) of pure alcohol. This is approximately the amount an average adult can process in one hour.
Units = (Volume in ml × ABV%) ÷ 1000
Example:
Pint of 4% beer = (568 × 4) ÷ 1000 = 2.3 units
UK Drinking Guidelines
What Does 14 Units Look Like?
- 6 pints of 4% beer
- 6 medium glasses (175ml) of 13% wine
- 14 single measures (25ml) of 40% spirits
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Calculate alcohol units in your drinks and track your weekly consumption against UK guidelines. Get instant results with our Alcohol Unit Calculator. You may also find our BAC Calculator, Calorie Calculator and BMI Calculator useful.
Units in Common Drinks
Beer and Lager
| Drink | Volume | ABV | Units |
|---|---|---|---|
| Pint of regular lager | 568ml | 4% | 2.3 |
| Pint of premium lager | 568ml | 5% | 2.8 |
| Can of lager | 440ml | 4% | 1.8 |
| Bottle of lager | 330ml | 5% | 1.7 |
Wine
| Drink | Volume | ABV | Units |
|---|---|---|---|
| Small glass | 125ml | 12% | 1.5 |
| Standard glass | 175ml | 12% | 2.1 |
| Large glass | 250ml | 12% | 3.0 |
| Bottle of wine | 750ml | 12% | 9.0 |
Spirits
| Drink | Volume | ABV | Units |
|---|---|---|---|
| Single measure (pub) | 25ml | 40% | 1.0 |
| Double measure | 50ml | 40% | 2.0 |
| Bottle of spirits | 700ml | 40% | 28.0 |
Processing Time
Your body processes alcohol at roughly 1 unit per hour. After 6 units at 11pm, you won't be alcohol-free until 5-7am.
Binge Drinking
The NHS defines binge drinking as drinking more than 8 units (men) or 6 units (women) in a single session.
How Alcohol Unit Calculations Work: The Methodology
The UK alcohol unit was introduced in 1987 as a simple way to quantify alcohol consumption. One unit equals 10 millilitres (ml) or 8 grams of pure ethanol. The formula is straightforward: Units = (Volume in ml x ABV%) / 1,000. The ABV (Alcohol By Volume) percentage is displayed on all alcoholic drinks sold in the UK as a legal requirement.
This formula means that the number of units in a drink depends on both its volume and its strength. A pint (568ml) of 4% lager contains 2.3 units, but the same volume at 5.2% contains 2.95 units -- nearly 30% more. Similarly, a 250ml glass of 14% wine contains 3.5 units, compared to 2.5 units for the same glass at 10% ABV. Both factors matter, and modern trends towards higher-strength wines and craft beers mean that drinks today contain more units than they did a generation ago.
Your body metabolises alcohol at approximately one unit per hour, though this varies significantly based on weight, sex, liver health, genetics, food consumption, and hydration. Women generally process alcohol more slowly than men due to lower levels of alcohol dehydrogenase (the enzyme that breaks down alcohol) and typically lower body water content. This is one reason the UK guideline is now the same 14 units for both sexes, despite men generally being larger.
Blood Alcohol Concentration (BAC) is a separate measurement from units, expressed as milligrams of alcohol per 100ml of blood (mg/100ml). The UK legal driving limit is 80mg/100ml in England, Wales, and Northern Ireland, and 50mg/100ml in Scotland. As a rough guide, one unit raises BAC by approximately 15-20mg/100ml in a 70kg person, though individual variation is substantial. There is no reliable way to calculate exactly when you will be under the limit based on units consumed, which is why the safest approach is not to drink at all if driving.
UK-Specific Context: Alcohol Guidelines and Regulations
The current UK Chief Medical Officers' guideline of 14 units per week was established in January 2016, replacing the previous gender-specific guidelines of 21 units for men and 14 units for women. The change was based on updated evidence showing that even moderate alcohol consumption carries health risks, including a demonstrated link between alcohol and several types of cancer (particularly breast, bowel, mouth, throat, and liver cancers).
The guidelines also recommend that if you do drink 14 units in a week, you should spread this over three or more days rather than concentrating it in one or two sessions. Having several drink-free days each week is also recommended. The NHS emphasises that there is no "safe" level of drinking -- the 14-unit guideline represents a low-risk level at which the risk of alcohol-related illness is kept acceptably low, not eliminated.
Alcohol misuse costs the NHS approximately £3.5 billion per year and is a factor in approximately 24,000 deaths annually in England alone. Public Health England (now the Office for Health Improvement and Disparities) estimates that around 10 million adults in England regularly drink above the recommended guidelines. The Alcohol Duty system in the UK was reformed in August 2023, with a new structure that taxes drinks based on their alcohol content rather than their category, meaning higher-strength drinks attract proportionally higher duty.
UK alcohol labelling regulations require all alcoholic drinks to display the ABV percentage, but unit information is currently voluntary. Many producers voluntarily include unit counts and the Chief Medical Officers' guidelines on their labels. Calorie labelling on alcohol is not yet mandatory in the UK, though there are proposals to introduce it. For reference, alcohol contains 7 calories per gram, making it almost as calorie-dense as fat (9 calories per gram).
The UK drink-drive limit has not changed in England, Wales, and Northern Ireland since 1967. Scotland lowered its limit to 50mg/100ml (from 80mg) in December 2014, aligning with most European countries. Penalties for drink-driving in England and Wales include a minimum 12-month driving ban, an unlimited fine, and up to 6 months in prison. Causing death by careless driving while over the limit carries a maximum sentence of 14 years.
Worked Examples: Calculating Units in Common UK Drinking Scenarios
Example 1: Friday Night at the Pub
3 pints of 4.5% premium lager + 1 double gin and tonic (50ml of 40% gin)
Lager: 3 x (568 x 4.5) / 1,000 = 3 x 2.56 = 7.67 units
Gin: (50 x 40) / 1,000 = 2.0 units
Total: 9.67 units -- nearly 70% of the entire weekly allowance in one session.
Processing time: Approximately 10 hours before alcohol-free.
Example 2: Weekend Wine with Dinner
Sharing a bottle of 13.5% wine (750ml) between two people over Saturday dinner.
Per bottle: (750 x 13.5) / 1,000 = 10.13 units
Per person (half bottle): 5.06 units
If each person also has a pre-dinner aperitif (125ml glass of 12% prosecco = 1.5 units), their total is 6.56 units -- nearly half the weekly allowance.
Example 3: Tracking a Moderate Week
Monday: 0 units (drink-free) | Tuesday: 0 | Wednesday: 2 pints of 3.8% session ale = 4.3 units | Thursday: 0 | Friday: 2 glasses of 12% wine (175ml each) = 4.2 units | Saturday: 1 pint of 5% craft IPA = 2.8 units | Sunday: 0
Weekly total: 11.3 units -- within the 14-unit guideline, spread over 3 days with 4 drink-free days.
Common Mistakes and Tips
Frequently Asked Questions
How many calories are in alcoholic drinks?
A pint of 4% lager contains approximately 180 calories, a 175ml glass of 12% wine contains about 130 calories, and a single measure of spirits with a mixer contains 50-100 calories (depending on the mixer). A bottle of wine contains roughly 600 calories. The NHS describes these as "empty calories" because alcohol provides no nutritional benefit. Someone drinking 14 units per week from wine consumes approximately 1,000 additional calories weekly, equivalent to roughly 5-6 doughnuts.
Is it safe to drink alcohol while taking medication?
Many medications interact with alcohol. The NHS advises particular caution with painkillers (especially paracetamol, which combined with alcohol can cause severe liver damage), antibiotics (some types cause nausea when mixed with alcohol), antidepressants, blood pressure medications, and antihistamines. Always read the patient information leaflet and ask your pharmacist if you are unsure. Some medications, such as metronidazole, require complete alcohol avoidance.
What counts as "binge drinking" in the UK?
The NHS defines binge drinking as consuming more than 8 units in a single session for men, or more than 6 units for women. To put this in context, 8 units is approximately 3 pints of 5% lager or just over a bottle of 12% wine. Binge drinking significantly increases the risk of accidents, alcohol poisoning, and risky behaviour. According to the ONS, approximately 27% of UK adults report binge drinking at least once in the previous week.
Can I "save up" units and drink them all at the weekend?
No. The 14-unit guideline is explicitly not designed to be consumed in one or two sessions. Drinking 14 units in a single sitting constitutes heavy binge drinking and carries immediate health risks including alcohol poisoning, accidents, and heart rhythm disturbances. The guideline recommends spreading units over at least three days. The health risks of 14 units in one session are far greater than 14 units spread over a week, even though the total is identical.
Tips for Reducing Intake
- Have drink-free days: Aim for 3-4 per week
- Use smaller glasses: 125ml wine instead of 250ml
- Choose lower ABV: 3.5% beer instead of 5%
- Alternate with water: Soft drink between alcoholic drinks
- Set a budget: Decide your limit before you start
Getting Support
- Drinkline: 0300 123 1110
- Alcoholics Anonymous: 0800 9177 650
- Your GP: Confidential support
How long does it take for alcohol to leave my system and when is it safe to drive?
What support is available on the NHS if I want to reduce my alcohol intake?
Dr. Sarah Chen, PhD
Research Scientist, Public Health
Sarah holds a PhD in Public Health from the University of Edinburgh and has published research on UK health metrics and obesity trends. She translates complex medical data into practical, accessible guidance for everyday readers.