Alcohol Percentage in Blood Calculator

Blood Alcohol Content (BAC) Estimator

Use this calculator to estimate your Blood Alcohol Content (BAC) based on common factors. Please remember this is an estimation and should not be used to determine fitness to drive or operate machinery. Individual responses to alcohol vary greatly.

A standard drink typically contains about 0.6 fluid ounces (14 grams) of pure alcohol (e.g., 12 oz beer, 5 oz wine, 1.5 oz shot).

Male Female

Enter the approximate time elapsed since you started drinking.

function calculateBAC() { var drinksConsumed = parseFloat(document.getElementById("drinksConsumed").value); var bodyWeight = parseFloat(document.getElementById("bodyWeight").value); var gender = document.getElementById("gender").value; var timeElapsed = parseFloat(document.getElementById("timeElapsed").value); var bacResultElement = document.getElementById("bacResult"); var bacInterpretationElement = document.getElementById("bacInterpretation"); // Input validation if (isNaN(drinksConsumed) || drinksConsumed < 0) { bacResultElement.innerHTML = "Invalid input for drinks consumed."; bacInterpretationElement.innerHTML = ""; return; } if (isNaN(bodyWeight) || bodyWeight <= 0) { bacResultElement.innerHTML = "Invalid input for body weight."; bacInterpretationElement.innerHTML = ""; return; } if (isNaN(timeElapsed) || timeElapsed < 0) { bacResultElement.innerHTML = "Invalid input for time elapsed."; bacInterpretationElement.innerHTML = ""; return; } // Constants for BAC calculation (Widmark Formula) var alcoholGramsPerStandardDrink = 14; // Approximately 0.6 fl oz of pure alcohol var bodyWeightGramsPerLb = 453.592; var widmarkFactor; // r value var metabolismRate = 0.015; // BAC reduction per hour if (gender === "male") { widmarkFactor = 0.70; // Average for men } else { // female widmarkFactor = 0.58; // Average for women } // Total alcohol consumed in grams var totalAlcoholGrams = drinksConsumed * alcoholGramsPerStandardDrink; // Body weight in grams var totalBodyWeightGrams = bodyWeight * bodyWeightGramsPerLb; // Initial BAC before metabolism var initialBAC = (totalAlcoholGrams / (totalBodyWeightGrams * widmarkFactor)) * 100; // BAC after metabolism var finalBAC = initialBAC – (metabolismRate * timeElapsed); // Ensure BAC doesn't go below zero if (finalBAC = 0.250) { interpretation = "Severe impairment, potential for unconsciousness or death."; } else if (finalBAC >= 0.150) { interpretation = "Significant impairment, loss of balance, vomiting likely."; } else if (finalBAC >= 0.080) { interpretation = "Legally impaired in most places, poor muscle coordination, impaired judgment."; } else if (finalBAC >= 0.050) { interpretation = "Reduced coordination, impaired judgment, exaggerated behavior."; } else if (finalBAC >= 0.020) { interpretation = "Slight mood changes, relaxation, minor impairment of judgment."; } else { interpretation = "Little to no alcohol effect detected."; } bacInterpretationElement.innerHTML = interpretation; } // Run calculation on page load with default values window.onload = calculateBAC; .calculator-container { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f9f9f9; border: 1px solid #ddd; border-radius: 8px; padding: 25px; max-width: 600px; margin: 30px auto; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08); color: #333; } .calculator-container h2 { text-align: center; color: #2c3e50; margin-bottom: 20px; font-size: 1.8em; } .calculator-container p { font-size: 0.95em; line-height: 1.6; margin-bottom: 15px; } .calc-input-group { margin-bottom: 18px; } .calc-input-group label { display: block; margin-bottom: 8px; font-weight: bold; color: #555; font-size: 1em; } .calc-input-group input[type="number"], .calc-input-group select { width: calc(100% – 20px); padding: 12px; border: 1px solid #ccc; border-radius: 5px; font-size: 1em; box-sizing: border-box; transition: border-color 0.3s ease; } .calc-input-group input[type="number"]:focus, .calc-input-group select:focus { border-color: #007bff; outline: none; box-shadow: 0 0 5px rgba(0, 123, 255, 0.2); } .input-hint { font-size: 0.85em; color: #777; margin-top: 5px; margin-bottom: 0; } .calculate-button { display: block; width: 100%; padding: 14px 20px; background-color: #007bff; color: white; border: none; border-radius: 5px; font-size: 1.1em; font-weight: bold; cursor: pointer; transition: background-color 0.3s ease, transform 0.2s ease; margin-top: 25px; } .calculate-button:hover { background-color: #0056b3; transform: translateY(-2px); } .calculate-button:active { background-color: #004085; transform: translateY(0); } .calc-result-area { background-color: #e9f7ef; border: 1px solid #d4edda; border-radius: 8px; padding: 20px; margin-top: 30px; text-align: center; } .calc-result-area h3 { color: #28a745; margin-top: 0; margin-bottom: 10px; font-size: 1.5em; } .result-value { font-size: 2.2em; font-weight: bold; color: #28a745; margin-bottom: 10px; } .result-interpretation { font-size: 1.1em; color: #333; line-height: 1.5; }

Understanding Blood Alcohol Content (BAC)

Blood Alcohol Content (BAC) is a measure of the amount of alcohol in your blood, expressed as a percentage. For example, a BAC of 0.10% means that there are 0.10 grams of alcohol for every 100 milliliters of blood. This metric is crucial for understanding the level of intoxication and its potential effects on the body and mind.

How is BAC Calculated? The Widmark Formula

The calculator above uses a simplified version of the Widmark formula, a widely accepted method for estimating BAC. The core idea is to relate the amount of alcohol consumed to the total body water, as alcohol distributes throughout the body's water content. The formula generally looks like this:

BAC = (Alcohol Consumed in Grams / (Body Weight in Grams * r)) * 100 - (Metabolism Rate * Time Elapsed)

• Alcohol Consumed in Grams: This is derived from the number of standard drinks. A standard drink typically contains about 14 grams (0.6 fluid ounces) of pure alcohol.
• Body Weight in Grams: Your weight is converted to grams to match the units.
• 'r' (Widmark Factor): This is a distribution ratio that accounts for the proportion of water in a person's body. On average, men have a higher percentage of body water (around 68-70%) than women (around 55-58%). This is why gender is a critical factor in BAC calculation; for the same amount of alcohol, a woman will generally have a higher BAC than a man of the same weight.
• Metabolism Rate: The liver metabolizes alcohol at a relatively constant rate, typically around 0.015% BAC per hour. This means that over time, your BAC will decrease as your body processes the alcohol.
• Time Elapsed: The number of hours since you started drinking, allowing the calculator to account for the alcohol that has already been metabolized.

Factors Influencing Your BAC

While the Widmark formula provides a good estimate, several individual factors can influence your actual BAC:

• Body Weight: Heavier individuals generally have more body water, which dilutes the alcohol, leading to a lower BAC for the same amount consumed.
• Gender: As explained with the 'r' factor, women typically have less body water and higher body fat percentage than men, resulting in higher BACs.
• Number of Drinks: More alcohol consumed directly leads to a higher BAC.
• Time Elapsed: The longer the time since your last drink, the more alcohol your body has metabolized, leading to a lower BAC.
• Food Consumption: Drinking on an empty stomach allows alcohol to be absorbed into the bloodstream much faster, leading to a quicker and higher BAC peak. Food slows down this absorption.
• Medications: Certain medications can interact with alcohol, affecting its absorption or metabolism, potentially leading to higher BACs or enhanced effects.
• Genetics: Individual genetic variations can influence how quickly alcohol is metabolized.
• Hydration Level: Dehydration can lead to a higher BAC as there is less water to dilute the alcohol.

Understanding BAC Levels and Their Effects

Different BAC levels correspond to varying degrees of impairment:

• 0.02% – 0.03%: Slight mood elevation, relaxation, minor impairment of judgment.
• 0.05% – 0.06%: Reduced coordination, impaired judgment, exaggerated behavior, difficulty tracking moving objects.
• 0.08% (Legal Limit in many places): Poor muscle coordination, impaired balance, speech, vision, reaction time, and hearing. Difficulty detecting danger.
• 0.10% – 0.12%: Significant impairment of motor coordination and loss of good judgment. Speech may be slurred.
• 0.15% – 0.20%: Gross impairment, loss of balance, vomiting likely.
• 0.25% – 0.30%: Severe impairment, potential for unconsciousness, risk of aspiration (choking on vomit).
• 0.35% and above: Life-threatening, potential for coma, respiratory arrest, and death.

Important Disclaimer

This calculator provides an estimated Blood Alcohol Content (BAC) and should be used for informational purposes only. It is not a substitute for professional medical advice or a definitive measure of intoxication. Individual responses to alcohol can vary significantly due to numerous factors not fully captured by this simplified model. Never rely on this calculator to determine your fitness to drive, operate machinery, or make decisions regarding your safety or the safety of others. If you have consumed alcohol, the safest choice is always to avoid driving or engaging in activities that require full mental and physical faculties.