Estimate your blood alcohol content based on drinks consumed, weight, and time. Know your limits.
Estimate blood alcohol level.
The BAC (Blood Alcohol Content) Calculator estimates the percentage of alcohol in your bloodstream based on your consumption, body weight, gender, and time elapsed. BAC is the standard measure used by law enforcement and medical professionals to assess intoxication levels, with legal driving limits typically set at 0.08% in the United States.
Understanding BAC helps you make informed decisions about alcohol consumption. Your body can only metabolize alcohol at a fixed rate—approximately one standard drink per hour. Drinking faster than this causes alcohol to accumulate in your blood, leading to impairment. Factors like body weight (larger people have more water to dilute alcohol), gender (women typically have higher BAC from the same amount due to body composition), and food intake all affect your BAC.
This calculator uses the Widmark formula, the most widely accepted method for BAC estimation. A "standard drink" contains 14 grams of pure alcohol—equivalent to 12 oz of beer (5%), 5 oz of wine (12%), or 1.5 oz of spirits (40%). Remember that actual impairment varies based on tolerance, medications, and individual factors. This is an estimate only and should never be used to determine if you're safe to drive.
One standard drink = 14 grams of alcohol. BAC decreases by ~0.015% per hour.
| BAC Level | Typical Effects | Impairment |
|---|---|---|
| 0.02-0.03% | Mild relaxation, slight euphoria | Minimal |
| 0.04-0.06% | Lowered inhibitions, warm feeling | Judgment affected |
| 0.07-0.09% | Impaired balance, speech, vision | Significant |
| 0.10-0.12% | Poor coordination, slurred speech | Severe |
| 0.13-0.15% | Blurred vision, lack of balance | Dangerous |
| 0.16%+ | Nausea, disorientation | Medical emergency risk |
A 160 lb man drinking 3 beers over 2 hours: BAC = ((42g) ÷ (72.6 kg × 0.68)) × 100 - (0.015 × 2) = 0.085% - 0.030% = 0.055% — just under the limit but still impaired.
Important: This calculator provides estimates only. Individual responses vary. Never drink and drive. Related tools: BMI Calculator, Calorie Calculator.
Widmark formula: BAC = (Alcohol grams ÷ (Weight × r)) × 100 - (0.015 × hours). r = 0.68 for men, 0.55 for women. One standard drink = 14g alcohol. BAC decreases ~0.015%/hour.
US legal limit is 0.08% for drivers 21+. Commercial drivers: 0.04%. Under 21: 0.00-0.02% depending on state. At 0.08% coordination and judgment are significantly impaired.
Your body metabolizes alcohol at ~0.015% per hour. After 3 drinks (0.09% BAC): 6 hours to reach 0%. Only time helps—coffee, food, and showers don't speed metabolism.