Drink-drive limit in Scotland: what 50 mg means in drinks
Short answer: in Scotland, the limit is 50 mg of alcohol per 100 ml of blood, or 22 µg per 100 ml of breath, lower than the 80 mg that applies in England and Wales. In practice, one pint of 4% lager leaves most men under it, but two pints put an average woman over, and a large glass of wine can be enough on its own for a smaller person. The Scottish Government’s own advice is simple: you cannot safely drink any alcohol and drive. A conviction means a ban of at least 12 months.
The limits in Scotland
Scotland lowered its limit in December 2014. It is now (mygov.scot):
| Test | Scotland | England, Wales, Northern Ireland |
|---|---|---|
| Breath | 22 µg per 100 ml | 35 µg per 100 ml |
| Blood | 50 mg per 100 ml | 80 mg per 100 ml |
| Urine | 67 mg per 100 ml | 107 mg per 100 ml |
The limit depends on where you are driving, not where you live or where your licence comes from. Drive from Carlisle to Glasgow after lunch, and the rules change at the border. The same 50 mg limit is used in Ireland and most of Europe, and England and Wales plan to adopt it too, as we explain in our article on the England and Wales limit.
What 50 mg means in pints and glasses
The limit is measured in your blood, not in drinks, so there is no fixed number. These estimated peaks assume one drink an hour, no big meal, and an average elimination rate:
| 1 pint of 4% lager | 2 pints of 4% lager | 1 large glass of wine (250 ml, 13.5%) | |
|---|---|---|---|
| Man, 70 kg | ~29 mg | ~51 mg | ~47 mg |
| Man, 80 kg | ~25 mg | ~42 mg | ~40 mg |
| Man, 90 kg | ~21 mg | ~34 mg | ~35 mg |
| Woman, 55 kg | ~47 mg | ~86 mg | ~73 mg |
| Woman, 65 kg | ~38 mg | ~69 mg | ~61 mg |
| Woman, 75 kg | ~32 mg | ~57 mg | ~52 mg |
A few lessons from the table:
- One pint leaves most people under 50 mg, but a small woman can be close to it.
- Two pints put most women and lighter men over the limit.
- A large glass of wine holds more alcohol than a pint of lager: for most women, one large glass on its own is enough to be over.
These are estimates. Drinking on an empty stomach, a stronger beer, a generous measure or simply your own metabolism can add 10 to 20 mg. That is why mygov.scot warns that “one drink can put you over the limit”.
Penalties in Scotland
If you are convicted of drink driving in Scotland, you face (mygov.scot):
- a minimum 12-month driving ban;
- up to 6 months in prison, a fine of up to £5,000, or both;
- the offence on your licence for 11 years;
- the possible forfeiture of your vehicle.
Refusing to give a breath, blood or urine sample is treated just as seriously, and causing death while over the limit can lead to a very long prison sentence.
The morning after in Scotland
The lower limit makes the morning after much riskier. Alcohol leaves your body at roughly one UK unit per hour, and mygov.scot notes that it can take up to 24 hours or longer after heavy drinking. Compared with the 80 mg limit, you need about two extra hours to get under 50 mg.
After six pints finishing late in the evening, an 80 kg man can still be over 50 mg at 6am. After a wedding or a Christmas party, being over the limit at 8 or 9am is common. We work through three real examples in Am I still over the limit the morning after?
Did the lower limit work?
When Scotland cut its limit, researchers at the University of Glasgow compared road accidents before and after, and with England. They found no measurable fall in accidents, most likely because the change was not backed by more police checks or sustained campaigns (Lewsey et al., 2019).
That does not mean the limit is pointless: impairment starts well below 80 mg, and 50 mg is the norm across Europe. It means a lower limit works best when drivers know about it and expect to be tested. For you as a driver, the practical conclusion is the same: in Scotland, plan not to drink at all if you are driving.
How to stay on the right side of the limit
- If you are driving, do not drink. Alcohol-free beers are widely available in Scottish pubs.
- If you have been drinking, count your units and allow at least one hour per unit from your first drink, plus a margin for the lower limit. Our how many pints can I drink and still drive guide has more detail.
- Plan for the next morning, not just the night.
- Estimate your own curve: the ConsomAction calculator uses your weight, sex and actual drinks to show your blood alcohol hour by hour and the time you will be sober.
FAQ
What is the drink-drive limit in Scotland?
50 mg of alcohol per 100 ml of blood, 22 µg per 100 ml of breath, or 67 mg per 100 ml of urine. It has applied since December 2014.
Can I have one pint and drive in Scotland?
One pint of ordinary lager usually leaves an average man under the limit, but it can bring a smaller woman close to it, and stronger beers change the picture. The official advice is not to drink at all if you are driving.
Is the Scottish limit the same as in Ireland?
Yes, both use 50 mg per 100 ml of blood. Ireland also has a 20 mg limit for learner, novice and professional drivers.
Does the Scottish limit apply to English drivers?
Yes. The limit depends on where you are driving. A driver with an English licence is bound by the 50 mg limit as soon as they are on a Scottish road.
Further reading
- Drink-drive limit in England and Wales: 80 mg now, 50 soon?
- How many pints can I drink and still drive?
- Am I still over the limit the morning after?