๐บ Alcohol Metabolism Calculator
Estimate your blood alcohol concentration (BAC) and time to sober up based on drinks and body weight.
Drinks Consumed
Widmark Formula
BAC is estimated using the Widmark formula: BAC = Alcohol(g) / (Body Weight ร r ร 10)
r = 0.68 (male), 0.55 (female). Alcohol is metabolized at ~0.015% per hour.
BAC(%) = Alcohol(g) / (r ร Weight(kg) ร 10)
This calculator is for reference only. Actual BAC varies by individual. Never drink and drive.
Worked Examples
An 80 kg man drinking two 500 ml beers at 5 % reaches roughly 0.05 % BAC, above the 0.05 limit used in much of Europe.
A 55 kg woman drinking the same amount reaches about 0.08 %, near the upper limits used in England and Wales.
What BAC Estimates Hide
Formulas rely on average body water, so they are less accurate for very muscular or very lean people, and they ignore food, medication, liver health and drinking speed. Alcohol is eliminated at roughly 0.015 % per hour regardless of coffee, cold showers or sleep.
Frequently Asked Questions
- Does coffee sober you up?
- No. Caffeine masks drowsiness but does not lower BAC or improve reaction time; the liver clears alcohol at a fixed rate.
- How long until I can drive?
- Divide the BAC by 0.015 for hours. At 0.08 that is about five and a half hours, longer than most people expect.
- Are the legal limits the same everywhere?
- No: 0.05 in most of Europe, 0.08 in England, Wales and much of the US, 0.02 in Sweden and Norway, and effectively zero in Japan and for novice drivers in many countries.