Most accurate blood alcohol content calculator using the scientifically proven Widmark formula. Calculate your BAC instantly with our advanced calculator.
| Peak BAC | 0.00% |
| Estimated Sober Time | 0h 0m |
| Standard Drinks | 0 |
| Alcohol Consumed | 0g |
Discover our comprehensive BAC calculator features designed to help you accurately calculate blood alcohol content, plan your drinking responsibly, and understand when you'll be sober again.
Calculate exactly how long until your BAC returns to zero. Perfect for time planning after drinking sessions. This most accurate BAC calculator helps you determine your sober time.
Calculate BAC levels using the scientifically proven Widmark formula. Our BAC alcohol calculator provides accurate estimates for various drink types including beer, wine, spirits, and cocktails.
Male and female BAC calculator with different body water percentages. Women typically reach higher BAC levels than men for the same alcohol intake.
BAC calculator by weight - heavier individuals tend to have lower BAC for the same alcohol consumption. Enter your weight in kg or lb for precise results.
Age affects metabolism rates. Our advanced BAC calculator accounts for age as a factor in alcohol metabolism for more accurate estimates.
Support for multiple regions with different legal BAC limits. Our BAC calculator displays your status against regional standards including US, UK, Australia, and Europe.
Convert between different BAC measurement units including mg/dL to BAC, mg/L to BAC, promille to BAC, and BAC to promille. Essential for understanding international BAC standards.
Visual representation of your BAC level over time. Track your alcohol metabolism from peak BAC to zero BAC with an interactive chart.
Get personalized advice about BAC calculation methods, legal limits, alcohol effects at different levels, and responsible drinking guidelines.
This BAC calculator provides estimates only. Actual BAC levels can vary significantly based on individual factors including metabolism, food consumption, medications, health conditions, and genetic factors. Never drink and drive. This calculator is for educational purposes only and should not be used to determine if it's safe to drive or operate machinery.
Get personalized advice about BAC and alcohol consumption
Convert between different BAC units
Explore the different formulas used to calculate blood alcohol content. Each formula has its own strengths and is suited for different scenarios.
The Widmark formula is the most widely used method for calculating blood alcohol content. It was developed by Swedish chemist Erik Widmark in the 1920s and remains the standard for quick BAC estimations.
BAC = (Alcohol_Grams / (Body_Weight_Grams × r)) × 100
70kg male drinks 24g alcohol (2 beers)
BAC = (24 / (70000 × 0.68)) × 100 = 0.050%
Before considering elimination over time
General BAC estimation • Initial screening and quick assessments
The Watson formula provides more accurate BAC calculations by considering individual body water percentage based on age, height, and weight. It was developed by George Watson in the 1980s and is approximately 15-20% more accurate than Widmark.
BAC = (Alcohol_Grams / (Body_Weight_Kg × TBW)) × 100 - (Elimination_Rate × Hours)
TBW (Male) = 2.447 - 0.09156 × Age + 0.1074 × Height_cm + 0.3362 × Weight_kgTBW (Female) = -2.097 + 0.1069 × Height_cm + 0.2466 × Weight_kg
30-year-old male, 175cm, 70kg, drinks 24g alcohol over 2 hours
TBW = 2.447 - 0.09156 × 30 + 0.1074 × 175 + 0.3362 × 70 = 54.2%BAC = (24 / (70 × 0.542)) × 100 - (0.015 × 2) = 0.063 - 0.030 = 0.033%
Precise BAC calculations • Medical and research applications
The liver metabolizes alcohol at a relatively constant rate. This formula calculates how BAC decreases over time, which is essential for estimating when a person will be sober.
BAC_Final = BAC_Initial - (Elimination_Rate × Time_Hours)
Starting BAC of 0.08% after 5 hours
BAC_Final = 0.08 - (0.015 × 5) = 0.08 - 0.075 = 0.005%
Nearly sober after 5 hours
Estimating time to sober up • Planning safe driving times
A standard drink contains approximately 14 grams of pure alcohol. This formula provides quick estimation based on the number of standard drinks consumed, making it easy for everyday use.
BAC ≈ (Number_of_Drinks × 14) / (Body_Weight_Kg × r) × 100 - (0.015 × Hours)
70kg male drinks 4 standard drinks over 2 hours
BAC ≈ (4 × 14) / (70 × 0.68) × 100 - (0.015 × 2) = 1.18 - 0.03 = 1.15%
Everyday quick estimation • Social drinking situations
This formula calculates the maximum BAC reached after drinking, before elimination begins. It helps understand the peak danger level regardless of when it was reached.
BAC_Peak = (Alcohol_Grams / (Body_Weight_Grams × r)) × 100
70kg male drinks 56g alcohol (4 drinks)
BAC_Peak = (56 / (70000 × 0.68)) × 100 = 0.117%
Peak reached approximately 30-60 minutes after drinking
Understanding maximum risk • Comparing different drinking patterns
This formula calculates what your BAC was when you started drinking based on your current BAC and time elapsed. Useful when memory of drinking details is unclear.
BAC_Starting = BAC_Current + (Elimination_Rate × Hours_Elapsed)
Current BAC 0.05%, 3 hours since first drink
BAC_Starting = 0.05 + (0.015 × 3) = 0.05 + 0.045 = 0.095%
Peak BAC was approximately 0.095%
When drinking details are unclear • Retrospective analysis
| BAC Level | Effects |
|---|---|
| 0.00-0.02 | Normal behavior, slight relaxation |
| 0.02-0.05 | Mild euphoria, lowered inhibitions |
| 0.05-0.08 | Impaired judgment, reduced coordination |
| 0.08-0.10 | Poor motor control, slurred speech |
| 0.10-0.15 | Significant impairment, nausea |
| 0.15-0.20 | Major impairment, possible blackouts |
| 0.20-0.30 | Severe intoxication, unconsciousness |
| 0.30+ | Life-threatening, coma |
This calculator provides an estimate based on average values. Actual BAC can vary significantly based on the following factors:
Find answers to common BAC questions