BAC Calculator (Blood Alcohol Content)

Estimate your blood alcohol concentration (BAC). Educational tool only - NEVER drive after drinking. Use rideshare/taxi.

Affects BAC calculation due to body composition

1 lb = 0.453592 kg

1 drink = 14g alcohol (12oz beer, 5oz wine, 1.5oz liquor)

Hours since first drink

Widmark Formula:\nPeak BAC = (Alcohol (g) / (Body Weight (g) * r)) * 100\nCurrent BAC = Peak BAC - (0.015 * Hours)\n\nr (gender constant):\n- Male: 0.73\n- Female: 0.66\n\nStandard Drink = 14g alcohol\nMetabolism = ~0.015% per hour
Example:\nGender: Male\nWeight: 70 kg\nDrinks: 3 standard drinks\nTime: 2 hours\n\nAlcohol = 3 * 14g = 42g\nPeak BAC = (42 / (70,000 * 0.73)) * 100 = 0.082%\nCurrent BAC = 0.082 - (0.015 * 2) = 0.052%\n\nStatus: WARNING Impaired (below 0.08% but not safe)\nTime to 0.00%: ~3.5 hours\n\nWARNING DO NOT DRIVE - Use rideshare

What is BAC and how is it measured?

Blood Alcohol Concentration (BAC) is the percentage of alcohol in your bloodstream. 0.08% BAC = 0.08 grams of alcohol per 100 milliliters of blood. Measured via breathalyzer, blood test, or estimated using Widmark formula based on drinks consumed, time elapsed, weight, and gender.

What BAC level is considered legally drunk?

US legal limit: 0.08% BAC for driving (21+). Lower for commercial drivers (0.04%) and under 21 (0.00-0.02% zero tolerance). Above 0.08% = DUI/DWI. Impairment begins at 0.02%. Some countries have 0.05% limits. Penalties include fines, license suspension, jail time.

How fast does alcohol metabolize?

Average: 0.015% BAC per hour (one standard drink). Varies by: liver health, genetics, food intake, medications. Can't speed up: coffee, cold showers, exercise don't help. Only time reduces BAC. If 0.08% BAC, need ~5.5 hours to reach 0.00%. Plan ahead, don't drive.

Why does gender affect BAC?

Women typically have higher BAC than men from same alcohol due to: lower body water percentage (alcohol dilutes in water), smaller average body size, different enzyme levels. Formula uses gender coefficient: 0.73 for men, 0.66 for women (Widmark). Accounts for physiological differences.

Is this BAC calculator accurate for legal purposes?

NO. This is an ESTIMATE only. Factors affecting accuracy: individual metabolism, food, medications, health, drink strength variation. Never rely on calculators for legal decisions. Only official breath/blood tests are legally valid. If in doubt, don't drive. Use taxi/rideshare.