Estimate your blood alcohol level instantly — and know when you're safe
Estimate only. This uses the Widmark formula which does not account for food intake, hydration, medication, tolerance, or individual variation. Results must never be used to decide whether to drive. If in doubt — do not drive.
Your Details
Set to 0 to see peak estimated BAC right after drinking.
Estimated BAC
Relaxation, warmth, mild coordination changes.
BAC Timeline
Hours since first drink
Formula (Widmark): BAC% = (oz_alcohol × 5.14) ÷ (weight_lbs × r) − (0.015 × hours). The r factor is 0.73 for males and 0.66 for females, reflecting average body water distribution. Metabolism is modeled at ~0.015% BAC per hour — actual rates vary from 0.010–0.020% depending on the individual. Results are estimates only.
The Blood Alcohol Calculator uses the scientifically established Widmark formula to estimate your blood alcohol concentration (BAC) based on the number of drinks consumed, your body weight, biological sex, and time elapsed since your first drink. Get an instant BAC percentage, an impairment status, and a projected timeline showing when your BAC returns to zero — all in seconds.
The Widmark formula is the standard model used in forensic toxicology and by law enforcement, but it is an estimate. It does not account for food in your stomach (which slows absorption), individual metabolism speed, medications, hydration, or body composition. Real BAC can vary ±20–30% from the estimate, so results should never be used to decide whether to drive.
In the United States, one standard drink contains 0.6 fl oz (14 g) of pure alcohol — equivalent to a 12 oz beer at 5% ABV, a 5 oz glass of wine at 12%, or a 1.5 oz shot of 80-proof spirit at 40%. The calculator shows how many standard drinks your session represents.
The Widmark r factor (body water ratio) is 0.73 for males and 0.66 for females on average. Females typically have a higher percentage of body fat and lower total body water, so the same amount of alcohol is distributed in less water, producing a higher BAC than the same dose in a male of equal weight.
The average liver metabolizes alcohol at roughly 0.015% BAC per hour (one standard drink per hour for most people). So a BAC of 0.08% takes about 5–6 hours to fully metabolize. Coffee, food, water, or sleep do not speed up this process — only time does.