Drink driving explained

The honest answer to "am I OK to drive?" after drinking is that nobody can tell you yes. Here is why.

Your details

9.0 units, last drink 6 h ago

Do not drive

on average, about 3 h more for this alcohol to leave your body

Average clearanceabout 1 unit an hour, faster or slower for you
Hours for 9.0 units at the average rate9 h
Legal limit in England, Wales and Northern Ireland35 micrograms per 100 ml of breath, 80 mg per 100 ml of blood
Urine limit107 mg per 100 ml
What speeds it upnothing: not coffee, sleep, a shower or food
Clock timepick the time now to see when the average would pass
If convicted of driving over the limit (GOV.UK, Great Britain)up to 6 months in prison, an unlimited fine and a ban of at least 1 year
Over the limit in charge of a car, even parkedup to 3 months in prison, a fine of up to £2,500 and a possible ban

This page will never tell you it is safe to drive. Plenty of people clear alcohol more slowly than one unit an hour, and even below the limit alcohol slows your reactions. Never drink and drive. How fast alcohol clears varies a lot from person to person, so there is no reliable way to know you are under the limit, and you can still be over it the morning after. Scotland's limit is lower than the rest of the UK's. If you will drive, the safest choice is no alcohol at all.

If you have been drinking, do not drive: get a lift, a taxi or the bus. Worried about your drinking, or someone else's? Your GP can help, and Drinkaware and Drinkline (0300 123 1110, free and confidential) are there too. Call 999 if someone cannot be woken, is breathing slowly or is fitting after drinking.

The working

9 units, last drink 6 hours ago

On average the body clears about one unit an hour, so 9 units takes roughly 9 hours. Six hours on, that average says about 3 more hours. But that is only an average: plenty of people clear alcohol more slowly, food and drink speed change things, and alcohol affects driving well before you reach the limit. So the answer here is always the same: do not drive.

The law

Limits and penalties

Limit	England, Wales and NI	Scotland
Breath (micrograms per 100 ml)	35	22
Blood (mg per 100 ml)	80	50
Urine (mg per 100 ml)	107	67

Driving over the limit can mean up to 6 months in prison, an unlimited fine and a ban of at least 1 year, or 3 years for a second conviction in 10 years. Being in charge of a car over the limit, even sitting in it parked, can mean 3 months, a fine of up to £2,500 and a possible ban. You can also be charged with being unfit through drink below the limit.

Pick the time now and we show when the one unit an hour average would pass: 9 units, last drink 2 hours ago at 23:00, gives about 06:00. Many people take longer, so treat that as the earliest, never as a green light.

The limits

England, Wales and NI, and Scotland

Measure	England, Wales and NI	Scotland
Breath (micrograms per 100 ml)	35	22
Blood (mg per 100 ml)	80	50
Urine (mg per 100 ml)	107	67

The government says it is impossible to say how many drinks these limits equal. A drink or two can put some people over the Scottish limit.

The morning after

Where people get caught

A late night of 10 units can still be in your blood at 9am
Sleep, coffee, a shower and a fry up do not speed anything up
If you have to drive early, the safest plan is not to drink the night before
Nothing, not even how you feel, tells you that you are under the limit: get a lift, a taxi or the bus

Read with care

What this cannot tell you

This page explains; it never gives a go ahead.

Say you are safeIt is built never to. No calculator, app or breathalyser you buy can promise you are under the limit or safe.
Account for youWeight, sex, food, stress, medicines and your liver all change how much alcohol is in your blood.
Give legal adviceIf you have been stopped or charged, speak to a solicitor.

Questions

Common questions

How many drinks can I have and still drive?

There is no safe number. GOV.UK says it is impossible to turn the limit into drinks because it is different for everyone. The only safe amount is none.

Is the limit lower in Scotland?

Yes. In Scotland the limit is 22 micrograms per 100 ml of breath and 50 mg per 100 ml of blood, compared with 35 and 80 in the rest of the UK.

Can I drive the morning after?

You may still be over the limit, and you can be impaired below it. There is no reliable way to know you are under the limit. Drinkaware's advice is to avoid alcohol the night before you have to drive.

Does coffee sober you up?

No. You might feel more awake, but the alcohol is still there. Only time removes it.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

Before you get behind the wheel

If you have been drinking, do not drive: get a lift, a taxi or public transport, or wait until the next day and still be cautious. If drinking is on your mind, your GP can help, and Drinkline is free on 0300 123 1110.