What Exactly is an Alcohol Unit?
Before we can calculate how many units are in one glass of white wine, it's essential to understand what an alcohol unit is. In the UK, one unit is defined as 10ml of pure alcohol. This provides a standard measure that helps individuals track and control their intake, regardless of the drink's strength or size. The UK Chief Medical Officers recommend that adults should not regularly drink more than 14 units of alcohol a week, and this should be spread out over three or more days.
The Simple Formula for Calculating Units
The number of units in any alcoholic drink can be calculated using a straightforward formula. You just need to know the total volume of the drink in millilitres (ml) and the Alcohol by Volume (ABV) percentage, which is always printed on the bottle's label. The formula is:
Units = (Volume in ml x ABV %) / 1000
For example, to find the units in a 175ml glass of 13% ABV white wine, you would calculate: (175 x 13) / 1000 = 2.275 units. This is why a simple rule of thumb for counting units can be misleading—the numbers can quickly add up, even with a single glass.
How Glass Size and ABV Affect the Unit Count
Pubs, restaurants, and people's homes all use different sizes of glasses, and not all white wines have the same alcohol percentage. This variability is the main reason why the number of units in a 'glass' of wine is not consistent. Many pubs now serve wine in large 250ml glasses, which can contain the same number of units as two smaller 125ml glasses.
Units in Different Glass Sizes (based on 13% ABV)
- Small Glass (125ml): This is the smallest standard pour available in most places. At 13% ABV, a small glass would contain approximately 1.6 units. This is a good reference point for keeping a closer eye on your intake.
- Medium Glass (175ml): Many people consider this a 'standard' glass size when ordering out. At 13% ABV, a medium glass contains 2.3 units. Just six of these per week would put you right at the low-risk drinking guideline of 14 units.
- Large Glass (250ml): The most generous measure, and a common offering in bars and restaurants. At 13% ABV, a large glass contains a significant 3.3 units. Drinking just four large glasses over the course of a week would put you at nearly 14 units.
The Difference Between 'Wine' and 'White Wine'
While the unit calculation formula applies to all types of wine, white wine typically falls within a specific range of ABV, often between 11% and 14%. Dry whites like Sauvignon Blanc or Pinot Grigio are frequently found at the lower end of this scale, while richer, fuller-bodied whites may creep higher. However, it's not a universal rule, and some red and dessert wines can be significantly stronger. Always check the label for the specific ABV.
An Outbound Link for Further Reading
For more information on the NHS's low-risk drinking guidelines and advice on cutting down, visit the official NHS Better Health page.
Comparing Units in Different Wine Glasses
| Glass Size | 12% ABV Wine | 13% ABV Wine | 14% ABV Wine |
|---|---|---|---|
| Small (125ml) | 1.5 units | 1.6 units | 1.75 units |
| Medium (175ml) | 2.1 units | 2.3 units | 2.45 units |
| Large (250ml) | 3.0 units | 3.3 units | 3.5 units |
Tips for Monitoring Your White Wine Intake
Keeping track of your alcohol consumption can be difficult, especially with the wide variety of glass sizes and wine strengths available. Here are some practical tips to help you stay within low-risk guidelines:
- Use smaller glasses. Opting for a 125ml glass instead of a 250ml one immediately halves your unit intake per serving. Many pubs and restaurants now offer smaller measures, so be sure to ask.
- Check the ABV. Make a habit of checking the alcohol percentage on the bottle label. Choosing a lower-ABV white wine is one of the easiest ways to reduce your unit consumption without drastically changing your habits.
- Measure your pours at home. If you're pouring wine for yourself, it's easy to lose track. Using a measuring cup or an optic measure can help you pour accurate, consistent servings. At-home pours are often more generous than commercial ones.
- Alternate with alcohol-free drinks. Interspersing alcoholic drinks with water or soft drinks can help pace your consumption and reduce your total unit intake over an evening.
- Have alcohol-free days. Having several days a week where you don't consume alcohol gives your body a break and is a key part of the low-risk drinking guidelines.
Conclusion
To answer the question of how many units are in one glass of white wine, there is no single answer. The number of units is a variable determined by two key factors: the size of the glass and the wine's specific Alcohol by Volume (ABV). A small 125ml glass can contain as few as 1.5 units, while a large 250ml glass can easily contain over 3 units, especially with a higher ABV wine. Understanding how to calculate units and being mindful of serving sizes are crucial steps for anyone looking to monitor their alcohol intake and stay within recommended health guidelines.
