For many of us in the UK, a pint after work or a glass of wine with dinner is woven into the fabric of social life.
However, navigating the world of alcohol units can often feel confusing. You might find yourself wondering how a single glass of wine can push you over the daily recommendations, or why different beers have such vastly different unit counts.
Understanding these units is not just about following rules; it is about empowering yourself to make informed decisions for your long-term health. The current guidelines are designed to keep health risks from alcohol to a low level, yet surveys suggest many people struggle to translate liquid volume into actual alcohol content.
Whether you are looking to cut down for health reasons, manage your weight, or simply understand what you are consuming, getting to grips with alcohol units is the first step. This guide breaks down the science, the guidelines, and the practical realities of tracking your intake.
According to the NHS Live Well guidelines, understanding units is the most effective method for managing your consumption.
What Actually Is an Alcohol Unit?
The concept of the “alcohol unit” was introduced in the UK in 1987. It provides a standard way to measure the actual quantity of pure alcohol in a drink, regardless of the size of the container or the type of beverage.
One unit equals 10ml or 8g of pure alcohol.
This is roughly the amount of alcohol the average adult’s body can process in one hour. However, this is an average figure. Factors such as weight, age, sex, and metabolism mean everyone processes alcohol at a different rate.
The Role of ABV
To understand units, you must understand Alcohol by Volume (ABV). This percentage tells you how strong a drink is.
- Higher ABV means more units in a smaller amount of liquid.
- Lower ABV means fewer units, even if the glass size is the same.
For example, a pint of strong premium lager (5.2%) contains significantly more units than a pint of standard session lager (3.8%).
You can calculate units manually using this formula:
Strength (ABV) x Volume (ml) ÷ 1,000 = Units.
While doing maths at the pub isn’t ideal, tools like the Drinkaware unit calculator can help you track this accurately in real-time.
The Chief Medical Officers’ Guidelines
In 2016, the UK Chief Medical Officers (CMOs) updated the alcohol guidelines to reflect new evidence regarding the health risks associated with drinking.
The core advice is straightforward: to keep health risks from alcohol to a low level, both men and women are advised not to drink more than 14 units a week on a regular basis.
Spreading Your Intake
It is crucial to understand that these 14 units are not a target to aim for, but a limit. Furthermore, saving up all your units for a Friday night is strongly discouraged.
If you regularly drink as much as 14 units per week, it is best to spread your drinking evenly over three or more days.
Binge drinking—usually defined as drinking more than 6 units in a single session for women and 8 units for men—increases your risk of accidents, injury, and alcohol poisoning. You can read more about the risks of acute consumption in this Healthline guide to alcohol poisoning.
Long-Term Health Implications
Regularly exceeding these guidelines increases the risk of developing long-term health conditions.
The GOV.UK CMO report highlights that there is no completely “safe” level of drinking, but sticking to 14 units keeps the risk low.
Risks associated with persistent high intake include:
- Cancer: Alcohol is linked to seven different types of cancer, including breast, bowel, and mouth cancer. The risk increases with every drink. See the latest data from Cancer Research UK for a detailed breakdown.
- Heart Disease: While some older studies suggested benefits for the heart, newer evidence shows these are limited. High intake raises blood pressure and strains the heart muscle, as noted by the British Heart Foundation.
- Liver Disease: The liver processes alcohol, and excess creates scarring (cirrhosis), which is irreversible.
Decoding Your Favourite Drinks
It is easy to underestimate how many units are in a glass. Glass sizes in pubs and restaurants have grown larger over the years, and the ABV of wine and beer has generally increased.
Wine
Wine is a common culprit for accidental over-consumption. A “standard” glass used to be 125ml. Today, pubs typically serve 175ml (medium) or 250ml (large) measures.
- Small glass (125ml, 12%): 1.5 units.
- Medium glass (175ml, 13%): 2.3 units.
- Large glass (250ml, 13%): 3.3 units.
Drinking just one large glass of robust red wine can constitute nearly a quarter of your weekly allowance.
Beer and Lager
The strength of beer varies wildly. Craft beers and IPAs often have much higher ABVs than traditional ales.
- Pint of lower-strength lager (3.6%): 2 units.
- Pint of premium lager (5.2%): 3 units.
- Can of stout (440ml, 4.2%): 1.8 units.
If you drink five pints of premium lager over a weekend, you have already exceeded the 14-unit guideline.
Spirits
Spirits typically have a high ABV (around 40%), but are served in smaller measures (25ml or 35ml). However, home pours are often much larger than pub measures.
- Single shot (25ml, 40%): 1 unit.
- Double shot (50ml, 40%): 2 units.
Pre-mixed cans of gin and tonic or rum and cola often contain substantial amounts of sugar alongside the alcohol. Visual guides from Alcohol Change UK can be excellent for recognising these hidden volumes.
Quick Comparison Data Table
Use this table to check the unit content of common UK drinks at a glance.
| Drink Type | Volume | ABV (%) | Units (Approx) |
|---|---|---|---|
| Single Vodka & Mixer | 25ml | 40% | 1.0 |
| Small Glass of Wine | 125ml | 12% | 1.5 |
| Bottle of Lager | 330ml | 5% | 1.7 |
| Pint of Cider | 568ml | 4.5% | 2.6 |
| Large Glass of Wine | 250ml | 13% | 3.3 |
| Pint of Strong Beer | 568ml | 5.2% | 3.0 |
| Bottle of Wine | 750ml | 13.5% | 10.1 |
Practical Tips for Reducing Intake
Reducing your unit intake doesn’t mean you have to stop socialising. Small changes to your habits can significantly lower your total consumption.
1. Have Drink-Free Days
The NHS recommends having several drink-free days each week. This gives your system a chance to recover and helps break the habit of daily drinking.
2. Downsize Your Glass
If you are a wine drinker, swap the large 250ml glass for a 125ml measure. You will consume fewer units over the course of an evening without feeling like you are missing out.
3. Alternate with Soft Drinks
Drink a glass of water or a soda between every alcoholic drink. This slows down your intake and keeps you hydrated, which can help reduce hangovers.
4. Choose Lower Strength
Look for “session” ales or lower-alcohol wines. The difference between a 5.5% beer and a 4% beer adds up quickly over a few pints.
5. Monitor Your Mental Health
Sometimes we drink to cope with stress. If you find you are drinking to manage anxiety, seek resources from charities like Mind which offer support for mental health and substance use.
Frequently Asked Questions
Can I drive after one unit?
It is impossible to say. Alcohol affects everyone differently. The legal limit in England, Wales, and Northern Ireland is based on blood alcohol concentration, not units. The GOV.UK driving advice states the safest option is to avoid alcohol completely if you are driving.
Do alcohol units relate to calories?
Yes, alcohol is calorie-dense. Pure alcohol contains 7 calories per gram—almost as much as pure fat. A pint of lager can have the same calorie count as a slice of pizza. Check out BBC Good Food’s guide for a detailed look at the “empty calories” in booze.
Does eating food lower the units?
No. Eating food slows down the absorption of alcohol into your bloodstream, but it does not change the amount of alcohol (units) in the drink. Your body still has to process the same amount of toxins eventually.
The Bottom Line
Understanding alcohol units is a vital tool for maintaining a healthy relationship with drinking.
While the 14-unit weekly guideline helps minimise risk, it is important to listen to your body and remain honest about your consumption habits. Alcohol affects your liver, heart, and cancer risk, even at moderate levels.
By checking labels for ABV, measuring home pours, and taking regular drink-free days, you can enjoy alcohol socially while prioritising your long-term wellbeing.
If you are concerned about your drinking, speak to your GP or a local support service today.
