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How much alcohol can I drink before driving?

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The safest option is not to drink any alcohol at all if you plan to drive. Even a small amount of alcohol can affect your ability to drive, and there's no safe way to tell whether you're within the legal limit.

The limit varies depending on what country you're in. In England, Wales and Northern Ireland, the legal alcohol limit for drivers is:

  • 80 milligrams of alcohol for every 100 millilitres of blood in your body
  • 35 micrograms of alcohol for every 100 millilitres of breath
  • 107 milligrams of alcohol for every 100 millilitres of urine

In Scotland, the legal alcohol limit for drivers is:

  • 50 milligrams of alcohol for every 100 millilitres of blood in your body
  • 22 micrograms of alcohol for every 100 millilitres of breath
  • 67 milligrams of alcohol for every 100 millilitres of urine

There’s no safe way to calculate how much alcohol you can drink to stay below the legal limit. Alcohol's effect on the body varies between different people and depends on factors such as:

  • whether you're male or female
  • your age
  • your weight
  • whether you've eaten recently
  • the type of alcohol you're drinking
  • your stress levels

Effects of alcohol on driving

Any amount of alcohol affects your judgment and your ability to drive safely. You may not notice the effects but even a small amount of alcohol can:

  • reduce your co-ordination
  • slow down your reactions
  • affect your vision
  • affect how you judge speed and distance
  • make you drowsy

Alcohol can also make you more likely to take risks, which can create dangerous situations for you and other people.

How long do the effects last?

Alcohol takes time to leave your body. For example:

  • if you drink at lunchtime, you may be unfit to drive in the evening
  • if you drink in the evening, you may be unfit to drive the next morning

There's no quick way of sobering up. Drinking coffee or taking a cold shower won't help. Many hours after drinking, you could still be over the legal limit or unfit to drive.

Drink driving

In 2013, 260 people were killed and 1,100 were seriously injured as a result of drink driving. More than 70,000 people every year are caught drink driving.

If you fail a roadside breath test and are found guilty of drink driving, you may get:

  • six months in prison
  • an unlimited fine
  • a driving ban for at least 12 months
  • a criminal record

Getting home

If you're going to drink alcohol, plan beforehand how you'll get home without driving. You could book a taxi, use public transport or arrange a lift with someone who's not drinking.

Never offer alcohol to someone who's going to drive, and don't get in a car with someone who has been drinking.

Find out more about drinking and alcohol.

Content supplied byNHS
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Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.

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