UK drink-drive limits and alcohol unit calculator

Home
Car insurance
Car insurance guides
Alcohol unit calculator

Alcohol units calculator

1 of 3

This is what you've been drinking:

Type	Units

You've drunk

This is the recommended amount of no more than 14 units per week.

What's the UK drink-drive limit?

In England, Wales and Northern Ireland, the drink-drive alcohol limit for drivers is:

80mg of alcohol per 100ml of blood
107mg of alcohol per 100ml of urine
35 micrograms of alcohol per 100ml of breath

In Scotland, the drink-drive alcohol limit is reduced to:

50mg of alcohol per 100ml of blood
67mg of alcohol per 100ml of urine
22 micrograms of alcohol per 100ml of breath

What is a unit of alcohol?

One alcohol unit is measured as 10ml or 8g of pure alcohol.

A typical pint contains around one to two units. A glass of wine can be between one and a half to three units, depending on the strength and the size of the glass.

To put that in context, looking at 12% wine:

A standard glass (175ml) would be 2.1 units
A standard 750 ml bottle would be about 9 units

Beers, ciders and lagers can have a lot of variation due to their different strengths:

A pint of 4% lager e.g. Carling would be about 2.3 units
A pint of 6.6% Leffe Blonde would be about 3.8 units
A pint of 8.2% of Westons Vintage cider would be about 4.7 units

How many units can you drink and drive after?

Despite the legal limits there's simply no hard and fast rule. The rate at which your body absorbs alcohol depends on a number of factors, such as your sex, weight, what you’ve eaten and when, and your stress levels. You can get more info on this at GOV.UK.

Because alcohol affects each person differently, there's no fool proof way of drinking and staying under the limit, that’s why you should never drive after any alcoholic drink.

One person may be okay to drive after one or two drinks, while another is over the drink-drive limit after only one. Don’t forget you could also be well over the limit the next day after a night out, and if you’ve been drinking you should never sleep in your car, because the police view is that you’re still technically in control of the vehicle even if the engine is off. So if the police find you, you could be breathalysed and charged just as if you were driving.

You can get a rough estimate of your blood alcohol content (BAC) level using our morning after calculator.

We'll say it again - if you're driving, then don’t drink any alcohol.

How many units of alcohol should I drink a week?

The NHS says that you shouldn't drink more than 14 units in a single week. Even then, this should be spread across at least three days to avoid binge-drinking.

Our alcohol unit is intended as a rough guide only, and is not a substitute for common sense. If you're driving, don't drink. If you're drinking, don't drive.