Estimate Blood Alcohol Content (BAC) & Metabolism Time
Male
Female
(12oz beer, 5oz wine, or 1.5oz spirit)
0.000%
Understanding Alcohol Absorption Rate
The rate of alcohol absorption and metabolism is primarily determined by the Widmark Formula. This scientific calculation estimates the concentration of alcohol in a person's bloodstream based on body mass, biological sex, the amount of alcohol consumed, and the elapsed time.
The Widmark Formula
The formula used by this calculator is:
BAC = [ (Alcohol in grams / (Body Weight in grams × r)) × 100 ] – (β × Hours)
r (Gender Constant): 0.68 for men; 0.55 for women.
β (Metabolism Rate): The average rate at which alcohol is eliminated (roughly 0.015% per hour).
Standard Drink: Defined as 14 grams of pure ethanol.
Factors Influencing Absorption
While this calculator provides a mathematical estimate, several physiological factors can speed up or slow down how your body processes alcohol:
Food Intake: Eating a meal before or during drinking slows the rate of absorption into the small intestine.
Hydration: Dehydration can lead to higher blood alcohol concentrations.
Medications: Certain drugs can interact with alcohol, affecting how the liver processes it.
Body Composition: Muscle tissue contains more water than fat tissue, which helps dilute alcohol more effectively.
⚠️ IMPORTANT DISCLAIMER:
This calculator is for educational purposes only. It is NOT a legal tool and should NOT be used to determine if it is safe to drive or operate machinery. Individual metabolism rates vary significantly. Never drink and drive.
function calculateBAC() {
var gender = document.getElementById('gender').value;
var weightKg = parseFloat(document.getElementById('weight').value);
var drinks = parseFloat(document.getElementById('drinks').value);
var hours = parseFloat(document.getElementById('hours').value);
var resultDiv = document.getElementById('result-container');
var bacDisplay = document.getElementById('bac-value');
var statusDisplay = document.getElementById('bac-status');
var soberDisplay = document.getElementById('sober-time');
if (isNaN(weightKg) || isNaN(drinks) || isNaN(hours) || weightKg <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
// Constants
var alcoholGrams = drinks * 14; // 14g is the US standard drink
var weightGrams = weightKg * 1000;
var r = (gender === 'male') ? 0.68 : 0.55;
var beta = 0.015; // Average elimination rate per hour
// Widmark Formula
var rawBac = ((alcoholGrams / (weightGrams * r)) * 100);
var currentBac = rawBac – (beta * hours);
if (currentBac = 0.08) {
statusDisplay.innerText = "Legally Impaired (Above 0.08% Limit)";
statusDisplay.style.color = "#c0392b";
} else if (currentBac > 0.02) {
statusDisplay.innerText = "Significant Impairment – Do Not Drive";
statusDisplay.style.color = "#d35400";
} else if (currentBac > 0) {
statusDisplay.innerText = "Slight Impairment – Use Caution";
statusDisplay.style.color = "#f39c12";
} else {
statusDisplay.innerText = "System Likely Clear of Alcohol";
statusDisplay.style.color = "#27ae60";
}
// Estimate time until sober (0.00%)
if (currentBac > 0) {
var hoursToSober = currentBac / beta;
soberDisplay.innerText = "Estimated time until BAC reaches 0.00%: approximately " + hoursToSober.toFixed(1) + " additional hours.";
} else {
soberDisplay.innerText = "";
}
}