🍺 Alcohol Units Calculator
By ToolNimba Health Team · Reviewed by ToolNimba Editorial Review, health content review · Updated 2026-06-19
These figures are estimates for general information only and are not medical advice. The amount of alcohol your body handles depends on your weight, sex, food, medication and health, so the numbers here cannot tell you whether you are fit to drive or safe to drink. There is no completely safe level of drinking. If you are concerned about your drinking, please speak to a doctor or a qualified health service.
Estimates for information only, not medical advice. One UK unit is roughly metabolised per hour but this varies widely by person, food and health. Never use this to decide if you are safe to drive.
This alcohol units calculator turns any drink into the numbers that actually matter: UK alcohol units and US standard drinks. Enter the drink volume in millilitres and its ABV (the strength printed on the label), set how many you are having, and you instantly see the units, the grams of pure alcohol, and a rough guide to how long it takes to clear. Use the quick-fill menu for common drinks like a pint, a glass of wine or a single spirit measure.
What is the Alcohol Units Calculator?
Alcohol is measured by the amount of pure ethanol a drink contains, not by how much liquid is in the glass. A large glass of strong wine can hold more pure alcohol than a pint of ordinary beer, even though the beer looks like the bigger drink. To compare drinks fairly, health bodies use a fixed amount of pure alcohol as the yardstick. The UK uses the unit, where one unit is 10 ml (about 8 g) of pure alcohol. The United States uses the standard drink, defined as 14 g of pure alcohol. The two systems describe the same thing on different scales, which is why a single drink can read as several UK units but only one or two US standard drinks.
The UK unit formula is simple: units = volume in millilitres x ABV percent divided by 1000. A pint of 5% beer is 568 x 5 divided by 1000, which is 2.8 units. The grams of pure alcohol come from multiplying the volume by the ABV as a fraction and then by the density of ethanol, which is 0.789 g per ml: grams = ml x (ABV divided by 100) x 0.789. Dividing those grams by 14 gives the US standard drinks. Because the formulas only need volume and ABV, you can work out any drink, including home pours and cocktails, as long as you know roughly how strong it is.
ABV (alcohol by volume) is the single most important number on the label, and it has crept upward over the years. Many craft beers are now 6% to 8% rather than the old 4%, and a typical wine sits around 13% to 14% rather than 11%. A bigger glass at a higher strength means a drink that used to be one unit can now be three. Knowing the units also helps you track against guidelines: UK health advice is to keep below 14 units a week, spread over several days with drink-free days, while US guidance suggests up to one standard drink a day for women and two for men, with less always being safer.
When to use it
- Working out how many units are in a pint, a glass of wine or a measure of spirits before you order.
- Adding up a whole evening or a week of drinks to compare against UK or US low-risk guidelines.
- Comparing a strong craft beer against an ordinary lager to see how much the higher ABV adds.
- Logging home pours and cocktails, where the glass size and strength are not standardised.
How to use the Alcohol Units Calculator
- Enter the drink volume in millilitres (for example 568 for a UK pint).
- Enter the ABV percentage shown on the label or bottle.
- Set how many of that identical drink you are having.
- Or pick a common drink from the quick-fill menu to fill volume and ABV for you.
- Read off the UK units, US standard drinks, grams of pure alcohol, and the rough hours to clear.
Formula & method
Worked examples
A UK pint of beer, 568 ml at 5% ABV.
- UK units = 568 x 5 / 1000 = 2.84 units
- Pure alcohol grams = 568 x (5 / 100) x 0.789 = 22.4 g
- US standard drinks = 22.4 / 14 = 1.6 drinks
Result: About 2.8 UK units, 1.6 US standard drinks, 22.4 g of pure alcohol
A medium glass of wine, 175 ml at 13% ABV.
- UK units = 175 x 13 / 1000 = 2.28 units
- Pure alcohol grams = 175 x (13 / 100) x 0.789 = 18.0 g
- US standard drinks = 18.0 / 14 = 1.3 drinks
Result: About 2.3 UK units, 1.3 US standard drinks, 18.0 g of pure alcohol
A single UK spirit measure, 25 ml at 40% ABV.
- UK units = 25 x 40 / 1000 = 1.0 unit
- Pure alcohol grams = 25 x (40 / 100) x 0.789 = 7.9 g
- US standard drinks = 7.9 / 14 = 0.6 drinks
Result: Exactly 1.0 UK unit, 0.6 US standard drinks, 7.9 g of pure alcohol
UK units and US standard drinks for common drinks
| Drink | Volume | ABV | UK units | US standard drinks |
|---|---|---|---|---|
| Half pint of beer | 284 ml | 4% | 1.1 | 0.6 |
| Pint of beer | 568 ml | 5% | 2.8 | 1.6 |
| Bottle of beer | 330 ml | 5% | 1.7 | 0.9 |
| Small glass of wine | 125 ml | 12% | 1.5 | 0.8 |
| Medium glass of wine | 175 ml | 13% | 2.3 | 1.3 |
| Large glass of wine | 250 ml | 13% | 3.3 | 1.8 |
| Bottle of wine | 750 ml | 13% | 9.8 | 5.5 |
| Single spirit (UK) | 25 ml | 40% | 1.0 | 0.6 |
How one unit compares across systems
| Measure | Pure alcohol | Notes |
|---|---|---|
| 1 UK unit | 10 ml (about 8 g) | The UK reference amount |
| 1 US standard drink | 14 g (about 17.7 ml) | The US reference amount |
| 1 US drink in UK units | about 1.75 units | 14 g divided by 8 g per unit |
Common mistakes to avoid
- Counting drinks instead of units. A large 250 ml glass of 13% wine is over 3 UK units, not 1. Counting glasses or bottles rather than units badly underestimates how much alcohol you have actually had.
- Assuming all beer or wine is the same strength. A 4% lager and an 8% craft beer in the same glass differ by double. Always check the ABV on the label, because strengths have risen and vary a lot between brands.
- Treating UK units and US standard drinks as equal. They are different scales. One US standard drink is about 1.75 UK units, so the same drink reads as a bigger number in UK units. Do not mix the two when tracking.
- Using the hours-to-clear figure to decide if you can drive. The roughly one-unit-per-hour rule is a crude average that ignores your weight, sex, food and health. It must never be used to judge whether you are safe or legal to drive.
Glossary
- ABV
- Alcohol by volume, the percentage of a drink that is pure alcohol, printed on the label.
- UK unit
- A UK measure equal to 10 ml (about 8 g) of pure alcohol. Found as volume in ml times ABV percent divided by 1000.
- US standard drink
- A US measure equal to 14 g of pure alcohol, used to compare drinks of different sizes and strengths.
- Pure alcohol (ethanol)
- The intoxicating substance in drinks. Its density is about 0.789 g per ml, used to convert volume to grams.
- Low-risk guidelines
- Official advice on amounts that carry lower health risk, such as the UK limit of 14 units a week.
Frequently asked questions
How do I calculate alcohol units?
Multiply the drink volume in millilitres by the ABV percentage, then divide by 1000. For example, a 568 ml pint at 5% is 568 x 5 / 1000 = 2.8 units. This calculator does it for you and also shows US standard drinks.
How many units are in a pint of beer?
A UK pint (568 ml) of 5% beer is about 2.8 units. A weaker 4% pint is about 2.3 units, and a strong 6% pint is about 3.4 units, so the exact number depends on the ABV on the label.
What is the difference between a UK unit and a US standard drink?
A UK unit is 10 ml (about 8 g) of pure alcohol, while a US standard drink is 14 g. They measure the same thing on different scales, so one US standard drink is roughly 1.75 UK units.
How many units can I drink in a week?
UK health advice is to keep below 14 units a week, spread over three or more days with several drink-free days. There is no completely safe level, so less is always lower risk.
How long does it take to clear alcohol?
As a very rough guide the body clears about one UK unit per hour, so 6 units might take around 6 hours. This is only an average and varies with your weight, sex, food and health, so never rely on it to decide if you can drive.
How many units are in a glass of wine?
A small 125 ml glass of 12% wine is about 1.5 units, a medium 175 ml glass of 13% is about 2.3 units, and a large 250 ml glass of 13% is about 3.3 units. A full bottle of 13% wine is close to 10 units.
Sources
- Alcohol units , NHS (UK National Health Service)
- What Is A Standard Drink? , U.S. National Institute on Alcohol Abuse and Alcoholism