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Most "UK BAC calculators" get this wrong. The drink drive limit is not the same across the United Kingdom.
England, Wales, and Northern Ireland use one limit. Scotland uses a stricter one. If you are checking your own numbers, using the wrong one matters.England, Wales, Northern Ireland: 80mg of alcohol per 100ml of blood (equivalent to a BAC of 0.08%).
Scotland: 50mg of alcohol per 100ml of blood (equivalent to a BAC of 0.05%).
This calculator lets you set the correct limit for where you actually are, not a generic "UK" number that is only true for part of the country.
● 3 calculation models ● State and country legal limits ● Live BAC curve
Used to estimate body water distribution — the biggest factor in BAC accuracy.
Average is 0.015%/hr. Genetics, liver health, and tolerance shift this between 0.010–0.020%/hr.
Log each drink as you go for the most accurate live curve.
Modeled absorption & elimination curve for your full session.
0 / 8 glasses
Water helps prevent dehydration and eases next-day symptoms, but it does not lower your BAC or speed up alcohol metabolism. Only time does that.
General effects by approximate BAC level. Individual response varies significantly.
| BAC | Typical Effects |
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Scotland lowered its drink drive limit from 80mg to 50mg back in December 2014, making it the stricter part of the UK ever since. England, Wales, and Northern Ireland kept the older 80mg limit, which is the same limit as the standard US 0.08% BAC number, just measured in different units.
As of January 2026, the UK government’s new Road Safety Strategy includes a consultation on lowering the England and Wales limit down to 50mg, to match Scotland. That is a proposal under consultation, not a change in the law yet. If it passes, England and Wales would move to the same 0.05% equivalent limit Scotland already uses. We will update this page if and when that becomes actual law.
The UK measures alcohol limits in milligrams per 100ml of blood, not as a straight percentage like the US does. The two are directly comparable:
The UK also sets limits for breath and urine tests, which use different numbers again (35 microgrammes per 100ml of breath in England, Wales, and Northern Ireland, 22 in Scotland), but the blood-based number is the one that lines up directly with a standard BAC calculator like this one.
There is no safe fixed number of drinks for either limit, because body weight, sex, and how fast you drink all change the result. As a rough idea, a pint of regular strength lager (around 4% ABV) can bring an average man close to the England and Wales limit after two pints within an hour, and closer to the Scottish limit after just one. Women generally reach both limits faster than men at the same drink count, because of differences in average body water.
This is why the safest advice from UK road safety campaigns, and the honest advice here, is the same: do not try to drink up to the limit and drive. Plan not to drive at all if you are drinking.
QUESTIONS
No. England, Wales, and Northern Ireland use 80mg per 100ml of blood (0.08% BAC). Scotland uses a stricter 50mg per 100ml (0.05% BAC).
As of early 2026, the UK government has opened a consultation on lowering the England and Wales limit to match Scotland’s 50mg. It has not passed into law yet. Until it does, the 80mg limit still applies in England, Wales, and Northern Ireland.
There is no fixed “number of units” that guarantees you are under the limit, because it depends on your weight, sex, how fast you drink, and what you have eaten. Two people who drink the same amount can land on different readings.
Food slows down how fast alcohol enters your bloodstream, which can lower your peak reading, but it does not reduce the total alcohol your body has to process. Coffee, cold showers, and sleep do not speed up how fast your liver clears alcohol. Only time does that.