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How Long After Drinking Can I Drive?

Quick answer: only drive once the alcohol is completely out of your system. The body clears roughly one UK unit (8 g of alcohol) an hour on average, and some people take much longer; nothing speeds it up. Use the calculator to estimate when the drinks you had will be gone.

This is an estimate, not a breath test. It cannot tell you that you are safe or under the limit to drive. Your real level depends on your body, health, food and medicines. If you have been drinking, do not drive: take a taxi, public transport, or ask a sober driver.

Body weight

Unit

Body

First drink at

What did you drink? (number of each)

Pint of beer or lager, 4% (568 ml)

Pint of strong beer or cider, 5% (568 ml)

Bottle or can of beer, 5% (330 ml)

US beer, 5% (12 oz / 355 ml)

Glass of wine, 13% (175 ml)

Large glass of wine, 13% (250 ml)

US glass of wine, 12% (5 oz / 148 ml)

Single spirit, 40% (25 ml, UK)

Shot of spirits, 40% (1.5 oz / 44 ml, US)

Double spirit, 40% (50 ml)

The legal limits

Drink-drive limits you may meet

England, Wales and Northern Ireland: 80 mg per 100 ml of blood (0.08%). UK limits in full
Scotland: 50 mg (0.05%), since 5 December 2014.
United States: 0.08% in every state except Utah (0.05%); under-21 drivers face zero-tolerance laws. US limits
Most of Europe: 0.05%, often lower or zero for new and professional drivers. Every European country
Every other country: see driving laws by country.

Being under a limit does not mean being unimpaired, and police can charge impaired driving below it.

Questions

Alcohol and driving — FAQ

How long after drinking can I drive?

The only way to be sure is not to drive until all the alcohol has left your body. On average the body clears about one UK unit (8 g of alcohol) an hour, but some people are much slower. A night of 6 pints of 5% beer is about 17 units, which can take 17 hours or more to clear, so many people are still over the limit the next morning.

Can I speed up getting alcohol out of my system?

No. Coffee, water, food, a cold shower, exercise or sleep do not make the liver work faster. Food eaten before drinking slows how quickly alcohol is absorbed, but it does not remove it. Only time does.

How many drinks can I have and still drive?

There is no safe number. The same drinks give very different blood-alcohol levels depending on body weight, sex, food, health and how fast you drink. Driving skills start to worsen with the first drink, which is why many countries set limits as low as 0.02% or zero for new drivers.

What is a unit of alcohol and a standard drink?

In the UK one unit is 10 ml (8 g) of pure alcohol: a pint of 4% beer is about 2.3 units and a 175 ml glass of 13% wine about 2.3 units. In the US a standard drink holds 14 g of alcohol: 12 oz of 5% beer, 5 oz of 12% wine or 1.5 oz of 40% spirits.

Can I be over the limit the morning after?

Yes. Alcohol drunk late at night is often still in the blood the next morning, and police in the UK and elsewhere regularly catch drivers who feel fine after sleep. If you have drunk heavily, plan not to drive the next morning.

How it works: the Widmark estimate (alcohol in grams ÷ (body weight × 0.68 for men or 0.55 for women)), cleared at an average 0.015% blood-alcohol per hour and, for the cautious figure, a slower 0.010% per hour. Real elimination rates vary from person to person. Nothing you enter leaves your device. See also drunk driving deaths by state and the deadliest holidays to drive.