Calculate Blood Alcohol Content 🇬🇧

Check your blood alcohol level instantly with our free BAC calculator. See how many units you've had, estimate time to sober up below the UK drink driving limit (80mg/100ml), and stay safe on the road.

Do you fancy AI? Try our AI-powered BAC calculator.

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ℹ️ Information

CONTEXT
🌎 Country
Show results in
ABOUT YOU
Sex
Weight

Start time of drinking (optional) Time of your first drink (not required)

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🍹🍸🍺 Drinks

Drink {{index+1}} 🍷

🍺 🍷 🥃 🍺 🍹 Standard cocktail usually contains single shot of spirit. 🥂
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%

The results will show up here...
📈 Results

Current BAC

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Measured for Now

Drink-drive limit

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Based on UK law

Elimination rate

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Typical average

Standard Drinks

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Approx. consumed

Pure Alcohol

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Pure alcohol consumed
For your own safety, we recommend using a rate no higher than the average.
🟢 Status indicators
🔴 Over the legal limit – driving is illegal.
🟡 Approaching the legal limit – driving not advised.
🟢 Likely under the limit, but drive with care.
{{ afterLabel }} {{ $t('unit.' + units) }} Status
{{ result.time }} {{ result.drunkenness }} {{ result.statusLabel }}
Create a pop-up notification
📉 Sobriety Over Time
👮 Health impact and legal consequences
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Limit reached in: {{ legalLimitTimeLabel }} Sober in: {{ sobrietyTime }} Peak BAC: {{ peakBAC }}

💡 Advice: drink water, eat, and avoid driving until you are under the legal limit and ideally fully sober.

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Attention‼️ The results are only approximate, so make sure you are sober before driving.

About results ▼

📊 Current BAC

Your Current BAC shows your estimated blood alcohol concentration right now as a percentage. This number reflects how much alcohol is in your bloodstream and is used to assess impairment.

🚔 Legal limit

In the United States and Canada, the standard legal driving limit for fully licensed adults is 0.08 % BAC. Exceeding this can result in DUI/DWI penalties, including fines and license actions.

🧪 Elimination rate

This shows the assumed average rate your body metabolizes alcohol — typically ~0.015 % BAC per hour. It’s an estimate of how fast your BAC decreases over time.

🍺 Standard Drinks

The number of Standard Drinks represents the approximate number of typical servings you’ve consumed (e.g., one beer, glass of wine, or shot), based on local standards for drink size.

🧴 Pure Alcohol

This is the amount of pure alcohol (in ounces) your body has absorbed so far, giving you a measure of total alcohol consumed.

⏱ Time vs. Sobriety Table

The table lists how your BAC is expected to change with each hour passed — and when a Start time of drinking is provided, it aligns these estimates with the exact time of day you began drinking. For example, if you started at 6:00 PM, the column will show your projected BAC at 6:00 PM (Now), 7:00 PM (1h), 8:00 PM (2h), etc., so you can clearly see when your BAC is likely to cross legal and safer thresholds as the day progresses. Icons or status indicators show whether the level is safe for driving at those specific clock times, making it easier to plan your departure or rest period.

📈 Sobriety Over Time Graph

A visual line chart plotting your estimated BAC decline over hours. It helps you see when your BAC drops below legal and safer levels.

😵 How Alcohol Affects You

This reference table shows ranges of BAC and typical effects on your body and behaviour — from mild alertness changes to significant impairment at higher levels.

⏰ Legal limit reached in / Sober in / Peak BAC

These summaries give quick key estimates:

  • Legal limit reached in: the time until your BAC likely falls below the legal driving limit.

  • Sober in: total time until BAC reaches ~0.000 %.

  • Peak BAC: the highest BAC value recorded in the session.

Data Used in Our UK Alcohol Calculator

To provide an accurate estimate of your blood alcohol content (BAC), our UK-specific alcohol calculator blood model requires the following data:

  1. Weight (kg): Your body mass significantly affects how quickly alcohol is absorbed and processed. Generally, higher weight slows down intoxication.
  2. Gender: Biological sex affects alcohol metabolism. Women typically have lower alcohol dehydrogenase activity, causing slower alcohol breakdown.
  3. Alcohol Volume (ml): The total volume of alcohol consumed helps determine your BAC. Enter the actual liquid amount in millilitres.
  4. Alcohol Strength (% ABV): Indicates the ethanol content in the drink. This figure is crucial in calculating pure alcohol consumed.
  5. The selected time of the first drink (optional): If you provide the clock time of the first drink, the calculator anchors results to the time of day and shows how sobriety changes across the day — this allows you to see your estimated sobriety for the current clock time. If you do not provide the first-drink time, the calculator presents sobriety relative to the elapsed time (hours passed) since the start of drinking, comparing levels by hours rather than mapping them to specific times of day.

Our system functions as a type of digital alcohol countermeasure system, helping users assess the likely effects of alcohol on their body based on science-backed formulas used in UK law enforcement and healthcare.

Drink Driving Laws in the United Kingdom

England, Wales, and Northern Ireland:

  • The legal blood alcohol concentration (BAC) limit is 0.08% (80mg of alcohol per 100ml of blood).
  • Breath limit: 35 micrograms of alcohol per 100ml of breath.

Scotland:

  • The legal limit is lower at 0.05% (50mg per 100ml of blood) and 22 micrograms per 100ml of breath.

UK police use breathalysers and other alcohol countermeasure systems to detect violations. Exceeding the limit can result in fines, bans, or imprisonment depending on severity and BAC level.

Common Drink Driving Penalties in the United Kingdom

  1. Fines
    • Fines can reach up to £5,000 depending on the severity and whether it’s a first or repeat offence.
  2. Driving Ban
    • Minimum 12-month disqualification for first offences.
    • Up to several years or permanent disqualification for repeat offences or extremely high blood alcohol content.
  3. Imprisonment
    • Up to 6 months for driving over the legal alcohol limit.
    • Up to 14 years if alcohol-impaired driving results in a fatality.
  4. Community Orders
    • May include unpaid work, rehabilitation, or alcohol treatment programmes.
  5. Alcohol Awareness & Education
    • Rehabilitation courses may reduce driving bans by up to 25%.
    • Part of broader alcohol law enforcement strategies in the UK.
  6. High-Risk Offender Scheme
    • Applies to drivers with very high blood alcohol content (BAC).
    • Medical clearance is required before reapplying for a licence.

Source: UK Government, DVLA, and Alcohol Law Enforcement Policies

Tips for Responsible Drinking in the UK

  • Keep within NHS guidelines: no more than 14 units per week spread over 3+ days.
  • Watch for alcohol poisoning signs: confusion, vomiting, slow breathing, or unconsciousness – seek emergency help if these occur.
  • Never drive after drinking – even a small amount affects your blood alcohol content and driving judgement.
  • Drink water between alcoholic beverages to stay hydrated and reduce intoxication risk.
  • Eat before and during drinking to slow alcohol absorption.

Source: NHS, Drinkaware, and Public Health England

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