What is an Alcohol Unit?
An alcohol unit is a standardised measure used in the UK to quantify the amount of pure alcohol in a drink. One unit equals 10 millilitres (or 8 grams) of pure ethanol. This simple metric allows consistent measurement across different drink types and strengths.
The formula for calculating units is straightforward:
Units = (ABV% × Volume in ml) ÷ 1000
For example, a standard 750ml bottle of wine at 12% ABV contains: (12 × 750) ÷ 1000 = 9 units. This calculation works for any alcoholic drink—beer, wine, or spirits—making it the universal measure for understanding alcohol consumption.
Units in a Bottle of Wine
A typical 750ml wine bottle contains between 4 and 15 units of alcohol, depending on its strength. The table below shows how many units are in a standard bottle across the full range of wine styles, from the lightest sparkling wines to fortified styles.
| ABV % | Wine Style | Units per 750ml |
|---|---|---|
| 5.5% | Moscato d'Asti | 4.1 |
| 8% | Light Sparkling | 6.0 |
| 9% | Everyday White | 6.8 |
| 11% | Alsatian White | 8.3 |
| 12% | Standard White/Red | 9.0 |
| 12.5% | New World White | 9.4 |
| 13% | Premium Red | 9.8 |
| 13.5% | New World Red | 10.1 |
| 14% | Full-bodied Red | 10.5 |
| 14.5% | Powerful Red | 10.9 |
| 15% | Concentrated Red | 11.3 |
| 20% | Fortified Wine | 15.0 |
The key takeaway: an average bottle of wine at 12% ABV contains approximately 9–10 units. This means a single bottle represents roughly two-thirds of the recommended weekly alcohol limit for UK adults.
Units in a Glass of Wine
The number of units in a glass depends on both the glass size and the wine's alcohol by volume. Standard UK serving sizes range from 125ml to 250ml, with 175ml being the most common restaurant pour.
| Glass Size | At 12% ABV | At 13% ABV | At 14% ABV |
|---|---|---|---|
| Small (125ml) | 1.5 units | 1.6 units | 1.8 units |
| Medium (175ml) | 2.1 units | 2.3 units | 2.5 units |
| Large (250ml) | 3.0 units | 3.3 units | 3.5 units |
At a restaurant, a standard 175ml glass of 12% wine contains 2.1 units. If you pour a generous home measure into a larger glass, you could easily exceed 3 units in a single pour. This is why using consistent glassware at home and being aware of your pour size matters.
Units by Wine Style
Different wine styles have distinctly different alcohol levels, which directly affects their unit content. Light whites and sparkling wines typically sit at 9–11% ABV, resulting in 6.8–8.3 units per bottle. Standard dry reds range from 12–14% ABV (9–10.5 units per bottle), whilst powerful New World reds, particularly from California and Australia, often reach 14–15% ABV or higher.
Fortified wines—Port, Sherry, and Madeira—sit at 15–22% ABV because spirit has been added to the wine. A standard glass of Port (50ml) contains around 1 unit, whilst a full pour (75ml) approaches 1.5 units. Rosés typically fall between whites and reds, usually 12–13% ABV.
UK Alcohol Guidelines
The current UK Chief Medical Officer's guidance recommends a maximum of 14 units per week for both men and women. Importantly, these units should be spread across at least three days—meaning binge drinking is discouraged even if your weekly total is within limits.
NHS Note: Drinking less alcohol is better for your health. There is no safe level of alcohol consumption. If you do drink, spreading your intake over at least three days per week reduces the risk associated with drinking.
To put this in perspective: two large glasses of wine (3.5 units) five nights a week equals 17.5 units, exceeding the 14-unit guideline. Conversely, enjoying a bottle of wine (9 units) at the weekend, supplemented by two glasses (4.2 units) mid-week, totals 13.2 units spread across multiple days—well within recommended limits.