an Email

Understanding Drink Driving Limits: How Many Units Can Land You in Trouble?

< Back to News Articles Summary

Drink driving is a serious and well-known criminal offence, but the specific boundaries of the drink driving limit can often feel hazy after a night out. For drivers in England, Wales, and Northern Ireland, and indeed throughout the UK, understanding what is considered the legal blood alcohol concentration (BAC) and how much alcohol could put you over the drink-drive limit can be helpful. So how many units of alcohol are too many? And what can you do to protect yourself if you accidentally cross that line?

Know Your Units: Understanding BAC

The UK has justifiably strict alcohol limits for getting behind the wheel. If you are caught drink driving, your breath, blood, or urine will be tested against this legal limit. The legal limit for alcohol consumption in England, Wales, and Northern Ireland is 80 milligrams of alcohol per 100 millilitres of blood, 35 micrograms of alcohol per 100 millilitres of breath, and 107 milligrams per 100 millilitres of urine. In Scotland, the legal limit for milligrams per 100 millilitres of blood is only 50. What these numbers translate to in terms of units of alcohol in actual drinks can take some careful calculations.

How to Translate Units to Drinks

While there is no hard and fast rule for how many units of alcohol are safe, we’ve often heard health advice to not exceed 14 units of alcohol a week. What does that really mean in pints of beer, glasses of wine or measures of spirits?

  • A standard UK drink contains about 8g of pure alcohol, known as one UK alcohol unit.
  • One UK unit equals about half a pint of normal-strength beer, a small glass of wine, or one single measure of spirits. A single strong pint or large glass of wine can have as many as three units.
  • While it varies from person to person, the general guidance states that it takes about one hour for the human body to metabolise one unit of alcohol. This means that men should aim to consume under two units per hour and women should stick to one unit per hour to ensure there is minimal alcohol left in their blood and allow time for their bodies to process the alcohol and stay under the limit. After just one or two drinks, it can take two hours or more before you are completely sober.

The Safe Limit Myth: How Factors Impact BAC

Even drinking minimal alcohol affects your judgement, reaction times, and vision, which can lead to devastating accidents even if you are below the legal drink driving limit. While it is best to avoid alcohol altogether before getting behind the wheel at all if you plan to drink, many people wonder, how many units can you drink and drive? The answer varies from person to person, meaning there is no foolproof way to calculate how much you can drink before exceeding the drink-drive limit. Your alcohol levels depend on numerous factors, including:

Individual Alcohol Metabolism

Everyone metabolises alcohol at different rates, and drinks that are safe for one person could make someone else over the legal limit or unfit to drive. Factors like body mass, sex, age, and even genetic factors contribute to how quickly you process alcohol. Smaller people will have less blood and water in their bodies, meaning they will have a higher blood-to-alcohol ratio than a larger person who drinks the same amount. Generally speaking, women can drink fewer alcohol units than men before reaching a BAC over the legal limit, and metabolise alcohol slower than men. Knowing your own limits is important for ensuring you don’t exceed the legal alcohol limit, especially before driving.

Food and Other Substances

Whether you have eaten recently plays a role in metabolising alcohol. Eating a substantial meal before or during drinking can slow the alcohol absorption rate into the blood, which can lower your BAC. Drugs, including prescription medication, common over-the-counter drugs, or illegal drugs can cause unexpected reactions and can cause a significant increase in BAC or impairment and put you over the legal alcohol limit. Always check a medication’s label before taking it with alcohol.

Stress and Illness

Stress levels and certain illnesses can impact your metabolism and cause slower alcohol processing, meaning that the number of alcohol units that were safe to drink a week ago could potentially put you over the drink-drive alcohol limit today.

Can You Calculate BAC?

Predicting your BAC is not straightforward. Online BAC calculators can estimate the effect of the amount of alcohol you drink, your weight, and the period over which you’re drinking, but this is a tool for estimation and should never be a barometer for driving safety. The fact remains that if you are pulled over by the police and there is alcohol detected in your system above the drink-drive limit, you will be taken to a police station and face the possibility of a drink driving conviction.

The Legal and Personal Consequences of Drink-Driving

If you are caught driving over the legal limit and are found guilty in criminal court, the penalties are severe. drink driving penalties can include:

  • A mandatory minimum one-year driving ban instead of penalty points on your licence (three years if convicted twice within ten years)
  • An unlimited fine (at the court’s discretion)
  • Imprisonment of up to six months for first-time offenders (in extreme cases, such as dangerous driving where others were endangered while you were driving under the influence of alcohol)
  • Community service
  • A criminal record. It takes five years for a conviction to become spent, meaning it will show up on Standard DBS checks by employers and landlords. Once your driving ban is lifted, you will likely pay up to 80% more for car insurance. A criminal record could also lead to trouble travelling since many countries require you to disclose criminal convictions before issuing a visa.
  • If your careless driving while over the legal alcohol limit causes someone’s death, you could be subject to life imprisonment.

The actual penalty you receive for exceeding the drink-drive limit will depend on the concentration of alcohol in your breath, blood, or urine, the severity of the offence, and the discretion of the court. The only way to guarantee you can drive safely is to not drink beforehand.

How a Solicitor Can Help

If you are pulled over after drinking, deemed to be over the legal limit or unfit to drive and find yourself facing a drink-driving charge, it is vital to seek help from a solicitor like #1 Motoring Solicitors. A solicitor can examine details of your case you might not have considered and provide you with the advice you need regarding your rights, the legal process, and potential defence strategies. Their role is to guide you through the complex court process and work to achieve the best possible outcome for your situation.

Prevention Is the Best Policy

Drink drive limits can serve as a guideline, but the only foolproof way to avoid drinking and driving is to abstain from drinking if you’re planning to drive. Before you head out, you and your group should choose a designated driver. Alternatively, you can plan to take public transport or use a service like a taxi or a rideshare to get home safely without risking anyone’s safety or penalties like a driving ban, unlimited fine, or imprisonment.

Safety Comes First

Knowing how many units you can drink can land you in trouble is helpful, but safety is paramount. By being informed and making responsible choices, you can protect yourself and others on the road. If in doubt, it’s always best to err on the side of caution and not drink before driving. After all, the cost of a few drinks is nothing compared to the potential cost of a drink driving offence. Even if you are under the drink drive limits, you could still be too impaired to drive safely. Stay safe, stay sober, and always seek out the safest means of travel if you’ve been drinking. Next time you’re out and about, remember to drink responsibly and stay within the legal limits – your safety and the safety of others depends on it.