We're supposed to be keeping an eye on how much we drink, but how many of us really know what a unit of alcohol is?

With so many different drinks and glass sizes, from shots to pints – not to mention bottles – it's easy to get confused about how many units are in your drink.

The idea of counting alcohol units was first introduced in the UK in 1987 to help people keep track of their drinking.

Units are a simple way of expressing the quantity of pure alcohol in a drink. One unit equals 10ml or 8g of pure alcohol, which is around the amount of alcohol the average adult can process in an hour. This means that within an hour there should be, in theory, little or no alcohol left in the blood of an adult, although this will vary from person to person.

The number of units in a drink is based on the size of the drink as well as its alcohol strength. For example, a pint of strong lager contains 3 units of alcohol, whereas the same volume of standard lager has just over 2 units.

• See common examples of drinks and their units

Calculating units

Using units is a simpler way of representing a drink's alcohol content – usually expressed by the standard measure ABV, which stands for alcohol by volume.

ABV is a measure of the amount of pure alcohol as a percentage of the total volume of liquid in a drink.

You can find the ABV on the labels of cans and bottles, sometimes written as "vol" or "alcohol volume" or you can ask bar staff about particular drinks.

For example, wine that says "12% ABV" or "alcohol volume 12%" means that 12% of the volume of that drink is pure alcohol.

You can work out how many units there are in any drink by multiplying the total volume of a drink (in ml) by its ABV (which is measured as a percentage) and dividing the result by 1,000.

• Strength (ABV) x volume (ml) ÷ 1,000 = units.

For example, to work out the number of units in a pint (568ml) of strong lager (ABV 5.2%):

• 5.2 (%) x 568 (ml) ÷ 1,000 = 2.95 units

To make things easier, use the units calculator to quickly calculate units and download a drinks tracker to your phone to keep on top of your drinking and get personalised feedback.

Drinks and units

A 750ml bottle of red, white or rosé wine (ABV 13.5%) contains 10 units.

See the guide below to find out how many units are in your favourite tipple.

*Gin, rum, vodka, whisky, tequila, sambuca. Large (35ml) single measures of spirits are 1.4 units.

The NHS recommends:

• Men should not regularly drink more than 3-4 units of alcohol a day.
• Women should not regularly drink more than 2-3 units a day.
• If you've had a heavy drinking session, avoid alcohol for 48 hours.

"Regularly" means drinking this amount every day or most days of the week.

If you regularly drink more than the recommended limits, try these simple tips to help you cut down.

Make a plan
Before you start drinking, set a limit on how much you’re going to drink.

Set a budget
Only take a fixed amount of money to spend on alcohol.

Let them know
If you let your friends and family know you’re cutting down and that it’s important to you, you could get support from them.

Take it a day at a time
Cut back a little each day. That way, every day you do is a success.

Make it a smaller one
You can still enjoy a drink but go for smaller sizes. Try bottled beer instead of pints, or a small glass of wine instead of a large one.

Have a lower-strength drink
Cut down the alcohol by swapping strong beers or wines for ones with a lower strength (ABV in %). You'll find this information on the bottle.

Stay hydrated
Drink a pint of water before you start drinking, and don't use alcohol to quench your thirst. Have a soft drink instead.

Take a break
Have the odd day each week when you don’t have an alcoholic drink.

Benefits of cutting down

The immediate effects of cutting down include:

• feeling better in the mornings
• being less tired during the day
• your skin may start to look better
• you’ll start to feel fitter
• you may stop gaining weight

Long-term benefits include:

Mood
There’s a strong link between heavy drinking and depression, and hangovers often make you feel anxious and low. If you already feel anxious or sad, drinking can make this worse, so cutting down may put you in a better mood generally.

Sleep
Drinking can affect your sleep. Although it can help some people fall asleep quickly, it can disrupt your sleep patterns and stop you from sleeping deeply. So cutting down on alcohol should help you feel more rested when you wake up.

Behaviour
Drinking can affect your judgement and behaviour. You may behave irrationally or aggressively when you’re drunk. Memory loss can be a problem during drinking and in the long term for regular heavy drinkers.

Heart
Long-term heavy drinking can lead to your heart becoming enlarged. This is a serious condition that can’t be completely reversed, but stopping drinking can stop it getting worse.

Immune system
Regular drinking can affect your immune system. Heavy drinkers tend to catch more infectious diseases.

Drinking guidelines

• Men should not regularly drink more than 3-4 units of alcohol a day
• Women should not regularly drink more than 2-3 units a day
• If you've had a heavy drinking session, avoid alcohol for 48 hours

"Regularly" means drinking this amount every day or most days of the week.

You may be surprised to find out how much you actually drink. Download a drinks diary (PDF, 697kb) to track your drinking over a week.

Did you know a standard glass of wine can contain as many calories as a piece of chocolate, and a pint of lager has about the same calorie count as a packet of crisps?

The average wine drinker in England takes in around 2,000kcal from alcohol every month.

Drinking five pints of lager a week adds up to 44,200kcal over a year, equivalent to eating 221 doughnuts.

Many drinkers add to their calorie count by having snacks, such as crisps, nuts or pork scratchings, to accompany their tipple.

A heavy drinking session is often followed by an unhealthy breakfast to help cope with a hangover, which again helps to pile on the pounds.

Going for a fry-up instead of your usual bowl of cereal can add an extra 450kcal to the calorie count from the night before.

The findings are based on an online survey of nearly 2,000 adults in England in March 2009 by YouGov for the Department of Health.

Regularly drinking more than the NHS recommends can have a noticeable impact on your waistline as well as cause less obvious but more serious health problems.

Many women don’t realise that two large glasses of white wine not only puts them over the recommended daily limit for regular alcohol consumption, but also provides them with nearly 20% of their recommended daily calorie intake, at approximately 370kcal in total.

Most people would baulk at consuming a full glass of single cream, but wouldn’t think twice about the calorie content of a couple of pints. But the calorie content is similar and, over time, excess alcohol intake can easily contribute to gaining weight.

Wine, beer, cider, spirits and all our favourite drinks are made from natural starch and sugar. Fermentation, and distillation for certain drinks, is used to produce the alcohol content. This helps explain why alcohol contains lots of calories – seven calories a gram in fact, almost as many as a gram of fat. And, of course, additional calories can be present in added mixer drinks.

Tips to avoid weight gain

To reduce the chances of gaining weight from drinking alcohol, follow these tips from the British Nutrition Foundation:

• Stick to your daily recommended units – men should not regularly drink more than 3-4 units of alcohol a day; women should not regularly drink more than 2-3 units a day. As an indication, a pint of lager (ABV 5.2%) and a 250ml glass of wine (ABV 12%) both contain 3 units of alcohol.
• Alternate an alcoholic drink with a glass of water – this will help to prevent you becoming dehydrated.
• Don’t drink on an empty stomach. If you do reach for snacks while drinking, opt for a healthier option – choose a sandwich instead of crisps or chips, or choose a chicken burger without mayonnaise instead of a kebab with garlic sauce.
• Drinking in rounds can mean you end up drinking more than you intended. Opt out and drink at your own pace.
• Try cutting down with a friend, as you’ll be more likely to stick to it with moral support.
• Eat a healthier dinner before you start drinking. Order or cook before you start drinking so you’re not tempted to go for the less healthy options.
• Pace yourself by taking small sips.
• Avoid "binge drinking" – some people are under the misapprehension that they can "save up" their units to splurge at the weekend.
• If you’re drinking white wine, why not add a splash of soda water to help the same number of units last longer?

For more help on reducing your alcohol intake, read Tips on cutting down.

How many calories are in your drink?

With a pint of beer the same as a packet of crisps, and a standard bottle of alcopop the same as three teacakes, the calories from alcohol soon add up.

*Calculated using Change4Life's Drinks Checker.

If you think only alcoholics and binge drinkers are putting their health at risk, think again.

Many people who see themselves as "social drinkers" are at risk of developing long-term health conditions because of the amount they regularly drink.

Most drinkers are unaware that regularly drinking more than the limits advised by the NHS can lead to a wide range of long-term health problems, including cancers, strokes and heart attacks.

More than 55% of people questioned in a YouGov poll thought that alcohol only damages your health if you regularly get drunk or binge drink.

The 2010 survey of 2,000 adults also found that 83% believed that regularly drinking more than the recommended daily limits didn’t put their long-term health at risk.

The survey suggests that 7.5 million people might be unaware of the damage their drinking could be causing.

The NHS recommends:

• Men should not regularly drink more than 3-4 units of alcohol a day
• Women should not regularly drink more than 2-3 units a day
• If you've had a heavy drinking session, avoid alcohol for 48 hours

"Regularly" means drinking this amount every day or most days of the week.

Read about the risks of drinking too much to find out how your drinking habits may be affecting your health.

Over the limit

More than 9 million people in England drink more than the recommended daily limits. About 15,000 people in England die from alcohol-related causes each year. About 32% of these deaths are from liver disease, 21% from cancer and 17% from cardiovascular illnesses, such as heart disease and strokes.

Typically, longer-term alcohol-related illness or death affect older people who drink more than the recommended daily limits and consider themselves to be "social drinkers".

Professor Nigel Heaton is a liver transplant consultant at King’s College Hospital, London. He says people who believe that drinking above the lower-risk guidelines is just normal social drinking may be raising their risk of developing alcohol-related illnesses.

“Some people think it’s natural to have a bottle of wine a night,” he says. “It seems respectable because you’re drinking with food and it’s not associated with any drunken behaviour or even feeling drunk.

"But if it happens regularly, you may have problems later on. Most of us believe that people with alcoholic liver disease are alcoholics. We often think, 'I’m not an alcoholic so I can’t get liver disease'.

“You may not be an alcoholic, but if the overall amount of alcohol you drink regularly exceeds the lower-risk guidelines, it may still cause serious harm.”

Track your drinking

To find out if you need to cut down, take the drinking self-assessment. It’ll help you assess the effects of your drinking. If it suggests that you’re drinking too much, you’ll get advice on how to cut down.

Monitor your drinking with the desktop alcohol tracker and drinks tracker for iPhone. This calculates the units of alcohol in your drinks, and it helps you work out whether you should cut down.

Because drinks come in all shapes and sizes, it can be hard to keep track of your units. Use the unit calculator to add them up and help you monitor the amount you drink.

Research suggests many people underestimate how much alcohol they drink. Download a drinks diary (PDF, 697kb) to track your drinking over a week.

If you think you drink too much, there are many ways to cut back. Read some tips on cutting down.