Blood Alcohol Calculator – Standard Drinks & 0.05% SA Limit 🇿🇦

Calculate your estimated Blood Alcohol Concentration (BAC) instantly. Track standard drinks, view your sobriety curve, and check your status against South Africa's 0.05% legal driving limit.

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ℹ️ Information

CONTEXT
🌎 Country
Show results indo
ABOUT YOU
Sex
⚖️ Weight

lbs

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

🕒

⏳ Or: hours ago —
0h6h12h18h24h

🍹🍸🍺 Drinks

Drink {{index+1}} 🍷

%

Maximum number of drinks reached.

The results will show up here...
📈 Results
Current BACPeak BAC {{ initialSobriety }}{{ unitSign }} Measured for Now · Legal limit {{ countryLimit }}{{ unitSign }}
Status:
Above the legal limit – do not drive. Close to the legal limit – driving not recommended. Safe to drive, but stay cautious.
Legal to drive: {{ legalLimitTimeLabel }}

Legal limit

{{ countryLimit }}{{ unitSign }}
Based on SA law ·

Elimination rate

{{ decayRateDisplay }}{{ unitSign }} / h
Assumed average

Standard Drinks

{{ standardDrinks }}🍺
Approx. consumed

Pure Alcohol

{{ results.length > 0 ? results[0].pureAlcoholMl : '0' }} {{ qunits }}
Pure alcohol consumed

Pure Alcohol (g)

{{ alcoholGrams }} g
Total ethanol consumed

Calories

{{ calories }} kcal
From alcohol only — mixers add more

Time over limit

{{ timeOverLimit || '0m' }}
Estimated duration above the legal driving limit
For your own safety, we recommend using a rate no higher than the average.
Current BACPeak BAC {{ initialSobriety }}{{ unitSign }} Measured for Now · Legal limit {{ countryLimit }}{{ unitSign }}
Status:
Above the legal limit – do not drive. Close to the legal limit – driving not recommended. Safe to drive, but stay cautious.
Legal to drive: {{ legalLimitTimeLabel }}
{{ afterLabel }} {{ $t('unit.' + units) }} Status
{{ result.time }} {{ result.drunkenness }}
  • Safe to drive, but stay cautious.
  • Close to the legal limit – driving not recommended.
  • Above the legal limit – do not drive.
Create a pop-up notification
📉 Sobriety Over Time
👮 Health impact and legal consequences
{{ item.title }}
Legal to drive: {{ legalLimitTimeLabel }} Sober in: {{ sobrietyTime }} Peak BAC: {{ peakBAC }}

💡 Tips: drink water, eat, and avoid driving until below the legal limit and ideally 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 South Africa, the legal driving limit for ordinary licence holders is 0.05% BAC (0.05 g per 100 ml). For professional drivers who hold a Professional Driving Permit (PrDP), the limit is lower at 0.02 g per 100 ml. Exceeding the limit is a criminal offence and can result in arrest, fines, and licence suspension.

🧪 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. A standard drink is generally counted as about 10 grams of pure alcohol.

🧴 Pure Alcohol

This is the amount of pure alcohol (in ounces/grams) 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 for calculations

In order to accurately calculate the effects of alcohol on the body, the following important data are required:

  1. Weight (kg):: Body mass has a direct impact on the absorption of alcohol. Higher weight determines a slower effect of alcohol on the body.
  2. Gender: The bodies of women and men process alcohol differently. Alcohol is broken down more slowly in women's bodies due to a lower amount of enzymes that break down alcohol.
  3. Amount of alcohol consumed (ml): It is necessary to indicate the exact volume of the alcoholic drink consumed in milliliters.
  4. Alcoholic strength (%): This indicator shows the concentration of ethanol in the drink. It is an important factor in determining the total amount of pure alcohol consumed.
  5. The 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.

These data are essential for accurately calculating the effects of alcohol on the body and assessing its impact on different individuals.

Drink Driving in South Africa

For ordinary licence holders:

  • It is illegal to drive with a blood alcohol concentration (BAC) of 0.05 g per 100 ml (0.05%) or higher, or a breath alcohol level of 0.24 mg per 1 000 ml or higher.

For professional drivers (PrDP holders):

  • A stricter limit applies: 0.02 g per 100 ml blood, or 0.10 mg per 1 000 ml breath.

Pending change:

  • A zero-tolerance limit (0.00) has been signed into law under the National Road Traffic Amendment Act but is not yet in force. Until it commences, the 0.05% limit applies.

Common Penalties in South Africa

  1. Arrest & criminal record
    • Drink driving is a criminal offence in South Africa. You can be arrested at the scene, and a conviction leaves you with a permanent criminal record.
  2. Fines
    • Heavy fines apply and increase significantly for higher BAC levels or repeat offences.
  3. Imprisonment
    • A conviction can carry a prison sentence, particularly for high readings, accidents, or repeat offences.
  4. Licence suspension
    • Your driving licence can be suspended or cancelled following a conviction.

Tips for Responsible Drinking

  • Limit your alcohol consumption – follow the “one drink per hour” rule (though this varies by person).
  • Consume alcohol with meals to slow down its absorption.
  • Drink a glass of water after each alcoholic drink.
  • Plan ahead: organise a designated driver, use public transport, or a rideshare service.

Source: World Health Organization.

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