BAC Calculator
Estimate your Blood Alcohol Content (BAC) based on drinks consumed, body weight, gender, and time elapsed since drinking. Check if you're over the 0.08% legal driving limit.
BAC Level Meter
Your BAC Level
Time Estimates
⚠️ Important Warning
This calculator provides estimates only. Many factors affect your actual BAC. Never drink and drive. If in doubt, don't drive.
Blood Alcohol Content Levels: Effects on the Body and Mind
| BAC Level | Status | Effects |
|---|---|---|
| 0.00% - 0.02% | Sober | No apparent effects, normal behavior |
| 0.02% - 0.05% | Mild Euphoria | Relaxation, slight mood elevation, reduced inhibition |
| 0.05% - 0.08% | Impaired | Reduced coordination, impaired judgment, lowered alertness |
| 0.08% - 0.10% | Legally Intoxicated | Significant motor impairment, slurred speech, poor balance |
| 0.10% - 0.15% | Severely Impaired | Blurred vision, nausea, difficulty walking and talking |
| 0.15% - 0.30% | Dangerous | Confusion, blackouts, vomiting, loss of consciousness possible |
| 0.30%+ | Life-Threatening | Alcohol poisoning, coma, respiratory arrest, potential death |
DUI Legal BAC Limits by Country
| Country | Legal Limit | Notes |
|---|---|---|
| 🇺🇸 United States | 0.08% | Under 21: 0.00-0.02% |
| 🇬🇧 United Kingdom | 0.08% | Scotland: 0.05% |
| 🇨🇦 Canada | 0.08% | Some provinces: 0.05% |
| 🇦🇺 Australia | 0.05% | Learners: 0.00% |
| 🇮🇳 India | 0.03% | One of the strictest limits |
| 🇩🇪 Germany | 0.05% | New drivers: 0.00% |
| 🇯🇵 Japan | 0.03% | Very strict enforcement |
Note: Laws change frequently. Always verify current limits for your jurisdiction. The safest choice is to not drive after consuming any alcohol.
Related Calculators
The Widmark Formula: How BAC Calculators Estimate Blood Alcohol
Blood Alcohol Content (BAC) measures the percentage of alcohol in your bloodstream. A BAC of 0.08% means 0.08 grams of alcohol per 100 milliliters of blood - the legal driving limit in most US states. This calculator uses the Widmark Formula, developed by Swedish scientist Erik Widmark in the 1930s, which remains the standard method for estimating BAC based on alcohol consumed, body weight, gender, and time elapsed since drinking started.
Widmark Formula Variables and Gender Differences
The Widmark formula calculates BAC as: BAC = (Alcohol consumed in grams) / (Body weight × r) - (0.015 × hours). The variable "r" is a distribution coefficient that accounts for body water content - 0.68 for males and 0.55 for females. Women typically have lower "r" values because they have proportionally more body fat (which doesn't absorb alcohol) and less body water. This means women generally reach higher BAC levels than men of the same weight after consuming identical amounts of alcohol.
What Factors Influence Your Blood Alcohol Level?
While the Widmark formula provides a useful estimate, many factors affect your actual BAC beyond what calculators can measure. Food consumption slows alcohol absorption - drinking on an empty stomach causes faster BAC rise. Rate of consumption matters too - spacing drinks over hours produces lower peak BAC than rapid consumption. Medication interactions can amplify alcohol effects, and liver health affects metabolism rate. Age, genetics, fatigue, and hydration status all influence how alcohol affects you. For calorie tracking while drinking, try our calorie calculator - alcoholic beverages often contain significant calories.
How Long Does It Take for Alcohol to Leave Your System?
Your liver metabolizes alcohol at a relatively constant rate of approximately 0.015% BAC per hour - equivalent to about one standard drink. This rate cannot be accelerated by coffee, cold showers, or exercise - these are myths. If your BAC is 0.15%, it will take roughly 10 hours to reach 0%. This is why morning-after impairment is a real concern - someone who stopped drinking at 2 AM with a 0.15% BAC would still be above the legal limit at 8 AM. Plan ahead and never assume you're sober just because you slept a few hours.
Standard Drink Measurements: What Counts as One Drink?
A "standard drink" contains approximately 0.6 ounces (14 grams) of pure alcohol. This equals: one 12-ounce beer at 5% ABV, one 5-ounce glass of wine at 12% ABV, or one 1.5-ounce shot of spirits at 40% ABV. However, many beverages exceed these standards - a craft IPA might be 7-10% ABV, and bar pours are often larger than standard measures. When using this calculator, count your drinks accurately - underestimating leads to dangerously underestimated BAC. For understanding your body composition and how it affects alcohol absorption, see our BMI calculator or body fat calculator.
Last Updated: January 2026 | Reviewed for accuracy