Blood Alcohol Concentration (BAC) Calculator
Estimate BAC from drinks, body weight, biological sex, and hours since your first drink. See an approximate BAC level, effects range, and time to sober.
Estimates only; not medical or legal advice. BAC varies by person and can rise after your last drink. Never use this tool to decide whether you can drive.
Estimate Your BAC Level
Enter your details and drink counts. This blood alcohol concentration calculator uses the Widmark formula and US standard drink sizes (or your custom size and ABV) to estimate BAC.
Distribution ratios are averages and may vary by individual.
One standard drink (US) equals about 0.6 fl oz of pure alcohol: 12 oz beer (5% ABV), 5 oz wine (12% ABV), or 1.5 oz spirits (40% ABV). Actual pours vary, so use Custom for cocktails or non-standard drinks.
Drinks Consumed
Counts below assume standard sizes. Use Custom for larger pours, cocktails, or higher ABV drinks.
Standard: 12 oz at 5% ABV
Standard: 5 oz at 12% ABV
Standard: 1.5 oz at 40% ABV
Enter any drink by size and ABV.
Leave size and ABV blank to count each as one standard drink.
Total alcohol estimated
0.00 fl oz
Assumed elimination rate
0.015% per hour (average)
Legal limit reference
0.08% BAC (varies)
Your BAC Estimate and Time to Sober
BAC Formula (Widmark)
This BAC calculator uses a simplified Widmark formula to estimate blood alcohol concentration from total alcohol, body weight, biological sex, and time since drinking began. It does not model absorption or drinking pace.
Formula
BAC = (A * 5.14 / (W * r)) - 0.015 * H
- A = total alcohol consumed (fl oz)
- W = body weight (lbs)
- r = alcohol distribution ratio
- H = hours since first drink
Important Notes
- Results are rough estimates, not medical or legal advice.
- Absorption and metabolism vary widely; BAC can rise after the last drink.
- Only breath or blood tests can measure BAC precisely.
- Never use a BAC estimate to decide whether you can drive.
BAC Effects by Level
Effects vary by person, context, and tolerance. This blood alcohol content guide is general information, not medical advice.
0.00% - 0.03%
Possible subtle impairment; relaxation may occur.
0.04% - 0.06%
Judgment and coordination may be reduced.
0.07% - 0.09%
Balance and reaction time may be impaired.
0.10% - 0.15%
Significant impairment and reduced control are likely.
0.16% - 0.20%
Severe impairment and higher risk of injury.
0.20% and above
Dangerous levels. Seek medical help if needed.
BAC Calculator FAQs
How accurate is this BAC calculator?
This blood alcohol concentration calculator provides a rough estimate based on average metabolism and standard drink assumptions. Actual BAC can differ, and only breath or blood tests can measure it. Do not use this estimate to decide whether it is safe or legal to drive.
What counts as a standard drink?
In the US, one standard drink equals about 0.6 fl oz of pure alcohol (12 oz beer at 5% ABV, 5 oz wine at 12% ABV, or 1.5 oz spirits at 40% ABV). Use Custom for larger pours or stronger drinks.
How long does it take to sober up?
Many people eliminate about 0.015% BAC per hour on average, but the rate varies by person and situation. The time-to-sober estimate is a guide, not a guarantee.
Is 0.08% the legal limit everywhere?
0.08% is a common reference, but legal limits vary by country, region, and driver status. Always follow local laws and choose safe transportation.
Can I speed up sobering?
Time is the only reliable way to lower BAC. Coffee, cold showers, and exercise do not remove alcohol from the body faster.
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