How long does alcohol stay in your blood?

On average, it takes about one hour for your body to break down one unit of alcohol. However, this can vary, depending on:

  • your weight
  • whether you're male or female
  • your age
  • how quickly or slowly your body turns food into energy (your metabolism)
  • how much food you have eaten
  • the type and strength of the alcohol
  • whether you're taking medication and, if so, what type

It can also take longer if your liver isn't working normally.

Read more about drinking and alcohol.

How much is one unit?

One unit is equivalent to 10ml or 8g of pure alcohol. There are roughly:

  • 2.1 units in a standard glass (175ml) of average-strength wine (12%)
  • 3 units in a large glass (250ml) of average-strength wine (12%)
  • 2 units in a pint of low-strength lager, beer or cider (3.6%)
  • 3 units in a pint of higher-strength lager, beer or cider (5.2%)
  • 1 unit in a single measure of spirits (25ml)

Use the alcohol unit calculator to work out how many units there are in a range of drinks.

Adding up your units

If you drink a large (250ml) glass of wine, your body takes about three hours to break down the alcohol.

If you drink one pint of beer, your body takes about two hours to break it down. One pint of strong lager is equivalent to three units, so this will take longer.

However, this time can vary depending on the factors mentioned above.

If you have a few drinks during a night out, it can take many hours for the alcohol to leave your body. The alcohol could still be in your blood the next day.

This means that if you drive the day after an evening of drinking, you could be over the legal alcohol limit. For more information, see How much alcohol can I drink before driving?

Know your units

To lower your risk of health problems, the NHS recommends that:

  • men should not regularly drink more than 3-4 units of alcohol a day
  • women should not regularly drink more than 2-3 units of alcohol a day

"Regularly" means drinking these amounts every day or on most days of the week.

Read more about the risks of drinking too much.

Further information:

Alcohol units: men

If men regularly drink more than three to four units of alcohol a day, it could add up to a serious health problem.

Media last reviewed: 06/09/2013

Next review due: 06/09/2015

Page last reviewed: 30/09/2013

Next review due: 29/09/2015