🍷 Blood Alcohol Concentration (BAC) Calculator
This calculator provides estimates only and should not be used to determine if you're safe to drive. BAC calculations vary based on many factors. Always use designated drivers or alternative transportation if you've been drinking. Never drink and drive.
BAC Calculator
What is BAC?
Blood Alcohol Concentration (BAC) is the percentage of alcohol present in your bloodstream. For example, a BAC of 0.08% means you have 0.08 grams of alcohol per 100 milliliters of blood. It is the standard measure used by law enforcement and medical professionals to determine intoxication and impairment. For example, a BAC of 0.08% means you have 0.08 grams of alcohol per 100 milliliters of blood — which is the legal driving limit in many countries.
Why BAC Matters:
Understanding your BAC is important because alcohol affects judgment, coordination, and reaction time. Even small amounts of alcohol can impair driving ability. In most places, the legal driving limit is 0.08%, but impairment often starts earlier, around 0.05%. Staying informed about your BAC helps you make safer choices for yourself and others.
How is BAC Calculated?
BAC depends on several key factors:
Alcohol consumed: type, volume, and strength of drinks.
Body weight: larger individuals dilute alcohol more effectively.
Gender: women typically reach higher BAC levels than men after the same number of drinks.
Time: the liver metabolizes alcohol at about 0.015 BAC units per hour.
Food intake: eating slows down alcohol absorption.
A common formula used is the Widmark equation, which considers alcohol intake, body weight, gender, and time since drinking.
BAC Levels and Their Effects:
Here’s a general guide to how BAC affects the body:
| BAC Level | Typical Effects on Body & Mind | Risks / Impairments |
|---|---|---|
| 0.01% – 0.02% | Mild relaxation, slight mood elevation, light body warmth. | Minimal impairment, but may reduce ability to perform two tasks at once. |
| 0.03% – 0.04% | Noticeable relaxation, slight euphoria, lowered inhibitions, mild impairment of concentration. | Reduced judgment, minor loss of alertness, may affect driving performance. |
| 0.05% – 0.06% | Clear impairment of judgment, reduced coordination, exaggerated emotions, lowered alertness. | Reduced ability to focus, delayed reaction time, crash risk significantly increases. |
| 0.07% – 0.09% | Impaired balance, speech, vision, reaction time, and hearing. Poor self-control and reasoning. | This range includes the legal driving limit (0.08%) in many countries; driving here is illegal and unsafe. |
| 0.10% – 0.12% | Slurred speech, loss of motor control, delayed reflexes, poor coordination. | Noticeable impairment of judgment and physical skills; high crash risk. |
| 0.13% – 0.15% | Severe lack of balance and coordination, blurred vision, dysphoria (anxiety, restlessness). | Greatly increased risk of injury, nausea may occur, loss of physical control. |
| 0.16% – 0.20% | Nausea, vomiting, dizziness, disorientation. Emotional swings from anger to sadness. | High risk of blackouts, accidents, and alcohol poisoning. |
| 0.21% – 0.29% | Severe confusion, staggering, inability to stand or walk properly. | High likelihood of blackout, memory loss, and physical accidents. |
| 0.30% – 0.39% | Extreme intoxication, potential unconsciousness, depressed vital functions (breathing, heartbeat). | Life-threatening alcohol poisoning, medical emergency. |
| 0.40%+ | Possible coma, respiratory failure, and death. | Critical medical emergency; immediate hospital care required. |
⚠️ Note: Individual tolerance, body weight, food intake, and health conditions can change how alcohol affects you. Even low levels can impair driving and decision-making.
Legal BAC Limits Around the World:
Different countries and states have different legal limits for driving:
USA: 0.08% for most drivers, 0.04% for commercial drivers, 0.00–0.02% for under 21.
UK: 0.08% in England & Wales, 0.05% in Scotland.
Europe: Most countries have limits between 0.02% and 0.05%.
Australia: 0.05% for most drivers, 0.00% for learner/probationary.
Always check your local laws before driving.
How Long Does Alcohol Stay in Your System?
On average, your body processes about 1 standard drink per hour. But this varies based on weight, metabolism, gender, and food intake.
For example:
1 beer (~5% alcohol) = ~1 hour to metabolize
1 glass of wine (~12% alcohol) = ~1.5 hours
1 shot of liquor (~40% alcohol) = ~2 hours
No amount of coffee, cold showers, or water can speed this up. Only time reduces BAC.
This Blood Alcohol Concentration (BAC) calculator is designed to give you an estimated BAC level based on the information you provide. Please remember that results may not be 100% accurate because alcohol affects everyone differently depending on factors such as age, health, medications, food intake, and personal tolerance.
Related Calculators
BSA Calculator, GFR Calculator
External Resources:
BSA Calculator on calculator.net
No, there is no quick fix. Only time allows your liver to metabolize alcohol, usually about one standard drink per hour. Coffee, cold showers, or exercise may make you feel alert but won’t lower your BAC.
The safest BAC is always 0.00%. Even at 0.02% to 0.05%, judgment and reaction time are impaired, raising accident risk. Staying alcohol-free before driving is the only truly safe option.
BAC measures alcohol in the blood, while BrAC measures alcohol in the breath using a breathalyzer. BrAC provides an estimate of BAC and is commonly used by police for roadside testing.
BAC depends on factors like body weight, gender, metabolism, and whether food was eaten. For example, women often reach higher BAC levels than men after the same number of drinks. Everyone processes alcohol differently.
On average, the body eliminates one standard drink per hour. Factors such as weight, gender, liver health, and food intake can speed up or slow down this process. Only time reduces BAC effectively.