How This Calculation Works
This calculator uses the Widmark formula to estimate Blood Alcohol Content. It considers the number of standard drinks, body weight, biological sex (which affects body water ratio), and time elapsed since the first drink.
Your body eliminates alcohol at approximately 0.015% BAC per hour. This is subtracted from the calculated peak BAC to estimate your current level.
A standard drink contains about 14 grams (0.6 oz) of pure alcohol: 12 oz beer (5%), 5 oz wine (12%), or 1.5 oz spirits (40%).
Common Mistakes to Avoid
- Underestimating drink count. Craft beers, large wine pours, and strong cocktails can equal 2–3 standard drinks each.
- Relying on this estimate to drive. This is a rough estimate only. Individual metabolism, food intake, medications, and health conditions all affect actual BAC.
- Thinking coffee or food sobers you up. Only time reduces BAC. Nothing speeds up alcohol metabolism.
Worked Example
Scenario: A 180 lb male has 4 standard drinks over 3 hours.
Raw BAC: (4 × 0.6) ÷ (180 × 16 × 0.73) × 100 = 0.114%.
Minus metabolism: 0.114 − (0.015 × 3) = 0.069%.
Status: Approaching legal limit. Do not drive.