Estimate your BAC instantly and make smarter, safer choices. Empower your night and avoid legal trouble with our accurate, science-backed calculator.
Quick tip: You don’t need to be a scientist to understand your BAC—just follow these steps.
Review the outcome and seek alternative transportation if BAC is near or above the legal limit.
BAC measures the concentration of ethanol in your bloodstream and is expressed as a percentage. For example, a BAC of 0.08% means there are 0.08 grams of alcohol per 100 milliliters of blood.
BAC = (A / (W × r)) × 100 - (β × t)Where:
Samantha (55kg) consumes 3 drinks over 1 hour:
A = 42g
W = 55,000g
r = 0.55
BAC = (42 / (55000 × 0.55)) × 100 - (0.015 × 1)
≈ 0.124%Outcome: Well above legal limits in most countries.
James (90kg) consumes 5 drinks over 4 hours:
A = 70g
W = 90,000g
r = 0.68
BAC = (70 / (90000 × 0.68)) × 100 - (0.015 × 4)
≈ 0.054%Outcome: Below legal limits but still mildly impaired.
Take control of your night—try the calculator now and make smarter, safer choices with confidence.
| Parameter | Example Value |
|---|---|
| Standard Drink | 14 grams of alcohol |
| Weight Conversion | 1 kg = 2.20462 lbs |
| Variable | Description | Example |
|---|---|---|
| r (Distribution Ratio) | Alcohol distribution coefficient | Male: 0.68, Female: 0.55 |
| β (Metabolic Rate) | Elimination per hour | 0.015 |
| A (Alcohol Consumed) | Total grams of ethanol | 3 drinks = 42g |
| t (Elapsed Time) | Hours since drinking began | 2.5 hours |