Estimated BAC for 3 drinks (Male)
Estimate for 160 lb, 1 hour(s) since the first drink. Educational estimate only — never a substitute for a breathalyzer.
Never drive after drinking any amount of alcohol, regardless of this number. Different inputs? Use the full BAC calculator above.
About this BAC calculator
This calculator estimates blood alcohol concentration (BAC) using the Widmark formula, a method developed in the 1930s that's still the basis for most simple BAC estimators today. It starts from the total ounces of pure alcohol consumed (number of standard drinks × 0.6 fl oz per US standard drink), divides that by your body weight and a gender constant that approximates differences in body water percentage, then subtracts the alcohol your liver has already metabolized based on time elapsed.
The gender constant (0.73 for men, 0.66 for women) exists because alcohol distributes through body water, and men's bodies contain a higher percentage of water on average than women's at the same body weight — so the same amount of alcohol produces a somewhat higher concentration in a woman's bloodstream. The formula also assumes a steady metabolism rate of about 0.015 BAC per hour, which is a population average for how quickly the liver breaks down alcohol.
Every part of this formula is an approximation of population averages, not a precise measurement of your body. Real BAC is affected by muscle-to-fat ratio, how much food is in your stomach, how quickly you drank (the Widmark formula assumes drinks were consumed close together), medications, liver health, and genetics — any of which can shift your actual BAC meaningfully above or below the number this calculator produces.
IMPORTANT SAFETY NOTICE: This calculator is provided strictly for educational purposes and cannot tell you whether it is safe for you to drive, operate machinery, or make decisions requiring full judgment. It is not a substitute for a breathalyzer or blood test, and individual metabolism varies significantly from the population averages this formula assumes. Never drive after drinking any amount of alcohol, regardless of what number this or any calculator shows you — impairment begins well before the legal limit, and the only truly safe BAC for driving is zero.
If you or someone you're with has had a lot to drink very quickly, shows confusion, vomiting, seizures, slow or irregular breathing, pale or bluish skin, or can't be woken up, that is a medical emergency — call for emergency help immediately rather than waiting to see if symptoms improve.
BAC calculator questions
How BAC is estimated, and important safety information.
How is BAC calculated?
This calculator uses the Widmark formula: it converts your number of standard drinks to ounces of pure alcohol (drinks × 0.6), divides that by your body weight and a gender constant, then subtracts the alcohol your body has metabolized based on hours elapsed since your first drink.
What counts as one standard drink?
In the US, one standard drink contains about 0.6 fl oz of pure alcohol — roughly a 12 oz beer at 5% ABV, a 5 oz glass of wine at 12% ABV, or a 1.5 oz shot of 80-proof liquor.
Is this BAC calculator accurate?
It's an estimate based on population averages, not a measurement of your actual blood alcohol level. Individual metabolism varies significantly based on muscle mass, food intake, medications, liver function, and genetics, so your real BAC could be meaningfully higher or lower than the estimate.
Is it safe to drive if my calculated BAC is under 0.08?
No. 0.08 is the legal driving limit in most US states, but impairment to judgment, reaction time, and coordination begins well below that number. This calculator is for educational purposes only and is not a substitute for a breathalyzer — never drive after drinking any amount of alcohol.
Why do men and women have different BAC results for the same drinks?
The Widmark formula uses a different constant for men (0.73) and women (0.66) because alcohol distributes through body water, and men's bodies contain a higher average percentage of water at the same body weight, so the same alcohol amount produces a higher concentration in a woman's bloodstream on average.
How long does it take for BAC to reach zero?
The body metabolizes alcohol at roughly 0.015 BAC per hour on average, which this calculator uses to reduce the estimate over time. This means it can take several hours for BAC to return to zero after drinking, and nothing — including coffee, cold showers, or exercise — speeds up that process.