🍷 Blood Alcohol Concentration (BAC) Calculator
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⚠️ Important Disclaimer:
This calculator provides estimates only and should not be used to determine if you're safe to drive. BAC calculations vary based on many factors. Always use designated drivers or alternative transportation if you've been drinking. Never drink and drive.
This calculator provides estimates only and should not be used to determine if you're safe to drive. BAC calculations vary based on many factors. Always use designated drivers or alternative transportation if you've been drinking. Never drink and drive.
Our free Blood Alcohol Concentration (BAC) Calculator estimates your BAC using the Widmark formula — the same method used in clinical and legal settings worldwide. Enter your weight, gender, time since your first drink, and the drinks you have consumed to instantly see your estimated BAC, impairment level, and time until your BAC reaches zero.
How to Use This Calculator
1
Enter your body weight and select your unit — pounds or kilograms.
2
Select your gender — this affects the Widmark distribution ratio used in the formula.
3
Enter the hours and minutes since your first drink so the calculator can account for alcohol already metabolised.
4
Select your drinks using the + and - buttons — Beer, Wine, Shot, Cocktail, and more are available.
5
Click Calculate BAC to see your estimated BAC, impairment status, effects, and time until zero.
BAC Levels and What They Mean
| BAC Level | Status | Key Effects | Safe to Drive? |
|---|---|---|---|
| 0.00 – 0.02 | Sober | No obvious effects, slight mood elevation | Yes |
| 0.02 – 0.05 | Mild Impairment | Warmth, relaxation, minor memory impairment | Not recommended |
| 0.05 – 0.08 | Increased Impairment | Reduced coordination, poor judgment | Illegal in many countries |
| 0.08 – 0.15 | Significant Impairment | Loss of balance, blurred vision, nausea | Illegal everywhere |
| 0.15+ | Severe / Dangerous | Loss of motor control, blackouts possible | Illegal everywhere |
Frequently Asked Questions
This calculator uses the Widmark formula — the same method used in clinical and legal BAC estimation worldwide. It provides a reliable estimate based on your weight, gender, drink intake, and time elapsed. However, individual factors such as liver function, medications, hydration, and food intake can affect real BAC. Never use any calculator to decide whether you are safe to drive.
Women typically have a lower percentage of body water and lower levels of alcohol dehydrogenase — the enzyme responsible for breaking down alcohol. The Widmark formula accounts for this with a lower distribution ratio for women (0.55 vs 0.68 for men). This means the same amount of alcohol produces a higher BAC in women compared to men of equal weight.
No. Coffee, food, water, and cold showers do not lower your BAC or speed up alcohol metabolism. Your liver processes alcohol at a fixed rate of approximately 0.015% per hour regardless of what you consume. Food slows alcohol absorption and delays peak BAC, but the same total amount of alcohol is eventually absorbed. Time is the only thing that lowers BAC.
Legal limits vary by country. The most common limits are 0.08% in the USA, UK (England/Wales), and Canada; 0.05% in Australia, most of Europe, and Scotland; and 0.00% in many other countries including zero-tolerance jurisdictions. These are legal thresholds — not safety thresholds. Impairment begins well before the legal limit and the only truly safe BAC for driving is 0.00%.
Want to Understand BAC in Depth?
Read our complete guide — how BAC is calculated, the Widmark formula explained, what affects your BAC, legal limits by country, and how long alcohol stays in your system.