Alcohol Units Calculator

The unit of alcohol is a simple way to measure the amount of pure alcohol in a drink. One unit equals about 10ml or 8g of pure alcohol and it's roughly equivalent to what an average-sized adult can process per hour.

This calculator can be used in two ways - you can enter the volume and strength of a drink to calculate the alcohol units it contains or you can add up your regular weekly drinking pattern to see if you are sticking within the low risk guidelines. As drinks vary so much in both volume and strength, calculating the number of units is the only reliable way to compare different drinks on an equal basis - for example one pint of beer, a glass of wine and a shot of spirits.

What is a unit of alcohol?

The concept of units was introduced in the UK in 1987 to help people keep track of their alcohol consumption. A unit does not refer to a particular volume of drink but rather a standard measure of pure alcohol.

As the amount of alcohol is roughly equivalent to what the body can break down per hour, it takes about two hours for a drink with two units of alcohol to be fully broken down. This varies from person to person and the more someone drinks, the slower their body processes the alcohol.

How to calculate alcohol content?

The amount of alcohol in a drink is determined by two factors; the volume of the drink and its alcoholic strength. The alcoholic strength is given on the label as an ABV (Alcohol By Volume) percentage, expressed as a proportion. A drink with "12% ABV" means that 12% of its volume is pure alcohol.

To calculate the amount of alcohol, multiply the volume in milliliters by the ABV and divide the result by 1,000.

For a pint (about 568ml) of strong lager with an alcohol content of 5.2% ABV:

So a pint (5.2% ABV) of this lager would contain about 3 units. The same pint of beer but with a lower alcohol content of 3.6% would only contain just over 2 units. This shows how much the strength affects the figure.

Alcohol content of common drinks:

As there can be a wide range of alcohol content for the same type of drink, these are average values. Always check the actual ABV and volume on the label.

A bottle of wine with a volume of 750ml and an alcohol content of 13.5% ABV contains about 10 units of alcohol. Drinking the whole bottle in one go is considered binge drinking.

UK guidelines for low-risk drinking

To minimize the health risks, both men and women should limit their regular alcohol consumption to no more than 14 units a week - this is equivalent to about six pints of normal strength beer or ten small glasses of low-alcohol wine.

If you do drink 14 units a week it is better to spread them over several days rather than drinking large amounts on one or two days. It's also a good way of reducing your intake if you cut out alcohol for a few days each week.

Excessive consumption and quantity per occasion

The risk is increased if you drink large amounts of alcohol at one time, rather than spreading the same amount over a longer period. In the UK, binge drinking is typically defined as consuming more than eight units for men or six units for women on one occasion.

This is roughly equivalent to one bottle of wine or about three pints of strong beer. Enter the amount of drink into a calculator to see when a night out tips into binge drinking territory.

Calories from alcohol:

The energy density of alcohol is almost as high as that of fat. Pure alcohol contains about seven calories per gram, so an alcoholic drink alone will contain around 56 calories per unit, even without sugar or mixers.

So a large glass of wine with about 3 units contains nearly 185 calories from the alcohol alone - roughly equivalent to one portion of ice cream. A normal pint of beer has around the same number of calories as a slice of pizza, and many drinks contain sugar so are usually even higher in calories. The calorie figures quoted here relate only to the alcohol itself.

How long does alcohol stay in your system?

As a rough guide the body processes about one unit per hour but this can be slower so a few drinks in the evening can have effects that last into the next morning. There is no reliable way to speed up this process whether by coffee, food or cold showers.

Symbols used:

This calculator is for general educational purposes only and does not constitute medical advice. Alcohol content and calorie values may vary by brand, measurement method and recipe and are estimates. There is no such thing as a safe level of alcohol consumption. If you have concerns about your drinking habits please consult your doctor or a support group.