BAC Calculator - Calculate Blood Alcohol Content
Free blood alcohol content calculator to estimate intoxication level and time until sober for safe drinking decisions
BAC Calculator
Results
What is a BAC Calculator?
A BAC Calculator is a free safety tool that estimates blood alcohol content based on drinks consumed, body weight, gender, and time elapsed using the Widmark formula. It calculates intoxication level and time until sober to help make responsible drinking decisions and avoid impaired driving or alcohol poisoning.
This calculator works for:
- Responsible drinking - Know your intoxication level
- Driving safety - Determine if safe to drive
- Party planning - Estimate alcohol effects
- Health awareness - Understand alcohol metabolism
To maintain overall health, check out our BMI Calculator to monitor healthy weight which affects alcohol metabolism and BAC levels.
For liver health monitoring, explore our Calorie Calculator to maintain healthy diet and reduce alcohol-related health risks.
To assess cardiovascular health, use our Blood Pressure Calculator as excessive alcohol consumption affects heart health.
For hydration needs, try our Daily Water Intake Calculator to stay hydrated and reduce alcohol dehydration effects.
How BAC Calculator Works
The calculation uses the Widmark formula:
Where variables include:
- A = Alcohol consumed in grams (drinks × 14g)
- W = Body weight in grams
- r = Gender constant (0.68 male, 0.55 female)
- H = Hours since drinking started
- 0.015 = Alcohol metabolism rate per hour
One standard drink contains 14g of pure alcohol. Alcohol metabolizes at 0.015% BAC per hour. Women have higher BAC due to less body water. Time is only way to sober up.
Key Concepts Explained
Standard Drink
12 oz beer (5% ABV), 5 oz wine (12% ABV), or 1.5 oz spirits (40% ABV). Each contains 14g pure alcohol.
Metabolism Rate
Liver metabolizes alcohol at 0.015% BAC per hour. Rate is constant and cannot be accelerated by coffee or food.
Legal Limit
0.08% BAC is legal driving limit in most US states. Lower limits (0.05%) in some countries. Zero tolerance for under 21.
Impairment Levels
0.02-0.05% mild, 0.05-0.08% moderate, 0.08-0.15% severe, 0.15-0.30% very severe, above 0.30% life-threatening.
How to Use This Calculator
Enter Weight
Input your body weight in pounds. Weight affects alcohol distribution in body.
Select Gender
Choose biological gender as it affects body water content and alcohol metabolism.
Count Drinks
Enter number of standard drinks consumed. See definition above for standard drink sizes.
Input Time
Enter hours since you started drinking. Alcohol metabolizes over time at constant rate.
Benefits of Using This Calculator
- •Prevent Drunk Driving: Know when BAC is below legal limit before driving to avoid DUI and accidents.
- •Avoid Alcohol Poisoning: Monitor BAC to prevent dangerous intoxication levels requiring medical attention.
- •Plan Safe Transportation: Calculate time needed to sober up or arrange alternative transportation.
- •Understand Impairment: Learn how alcohol affects judgment, coordination, and reaction time at different BAC levels.
- •Responsible Drinking: Make informed decisions about alcohol consumption based on body weight and gender.
- •Educational Tool: Understand alcohol metabolism and effects for health awareness and safety.
Factors That Affect Your Results
1. Food Consumption
Food slows alcohol absorption, reducing peak BAC. Drinking on empty stomach causes faster, higher BAC. Calculator assumes average absorption.
2. Drinking Speed
Rapid consumption causes higher peak BAC. Spacing drinks allows metabolism time. Calculator estimates based on total time drinking.
3. Individual Variation
Metabolism varies by genetics, liver health, medications, and tolerance. Calculator provides estimates, not exact measurements.
4. Drink Strength
Actual alcohol content varies. Craft beers (7-10% ABV) and strong cocktails contain more alcohol than standard drinks.
5. Health Conditions
Liver disease, medications, and health conditions affect alcohol metabolism. Consult healthcare provider about alcohol consumption.
Frequently Asked Questions (FAQ)
Q: What is BAC?
A: Blood Alcohol Content (BAC) is the concentration of alcohol in bloodstream measured as percentage. 0.08% BAC is legal limit for driving in most US states. BAC depends on drinks consumed, body weight, gender, and time elapsed.
Q: How is BAC calculated?
A: BAC is calculated using Widmark formula: BAC = (Alcohol consumed in grams / (Body weight in grams × r)) - (0.015 × Hours). r is 0.68 for men, 0.55 for women. Alcohol metabolizes at 0.015% per hour.
Q: How long does it take to sober up?
A: Alcohol metabolizes at approximately 0.015% BAC per hour. For 0.08% BAC, it takes about 5-6 hours to reach 0%. Only time sobers you up - coffee, cold showers, or food don't speed up alcohol metabolism.
Q: What BAC level is dangerous?
A: 0.08% is legal driving limit. 0.15-0.20% causes severe impairment. 0.30-0.40% can cause unconsciousness. Above 0.40% is potentially fatal. Seek medical help for BAC above 0.30% or signs of alcohol poisoning.
Q: Why do women have higher BAC than men?
A: Women have less body water (55% vs 68% in men) and different enzyme levels. Same alcohol amount produces higher BAC in women. Women also metabolize alcohol slower than men due to hormonal differences.