.bac-calc-wrapper {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
max-width: 800px;
margin: 20px auto;
padding: 25px;
border: 1px solid #ddd;
border-radius: 12px;
background-color: #fdfdfd;
color: #333;
box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}
.bac-calc-wrapper h2 {
color: #d9534f;
text-align: center;
margin-top: 0;
}
.calc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
margin-bottom: 25px;
}
@media (max-width: 600px) {
.calc-grid { grid-template-columns: 1fr; }
}
.input-group {
display: flex;
flex-direction: column;
}
.input-group label {
font-weight: 600;
margin-bottom: 8px;
font-size: 14px;
}
.input-group input, .input-group select {
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 16px;
}
.calc-btn {
grid-column: 1 / -1;
background-color: #d9534f;
color: white;
padding: 15px;
border: none;
border-radius: 6px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background 0.3s;
}
.calc-btn:hover {
background-color: #c9302c;
}
.result-display {
margin-top: 25px;
padding: 20px;
background-color: #f8f9fa;
border-radius: 8px;
border-left: 5px solid #d9534f;
text-align: center;
}
.result-value {
font-size: 32px;
font-weight: 800;
color: #d9534f;
display: block;
}
.result-status {
font-size: 18px;
font-weight: 600;
margin-top: 10px;
display: block;
}
.article-section {
margin-top: 40px;
line-height: 1.6;
}
.article-section h3 {
color: #2c3e50;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
}
.warning-box {
background-color: #fff3cd;
border: 1px solid #ffeeba;
padding: 15px;
border-radius: 6px;
color: #856404;
font-size: 14px;
margin-bottom: 20px;
}
Blood Alcohol Content (BAC) Calculator
Disclaimer: This calculator provides an estimate based on the Widmark formula. Biological factors, food intake, and metabolism vary significantly. Never drink and drive.
Biological Gender
Male
Female
Weight (kg)
Total Volume Consumed (ml)
Alcohol Percentage (ABV %)
Time Since First Drink (Hours)
Calculate Estimated BAC
Estimated Blood Alcohol Concentration:
0.00%
How Blood Alcohol Content is Calculated
Blood Alcohol Content (BAC) is a measurement of the percentage of alcohol (ethyl alcohol) in a person's bloodstream. This calculator uses the Widmark Formula , which is the gold standard for forensic alcohol estimation. The formula considers the amount of alcohol consumed, body weight, the gender-specific distribution of water in the body, and the rate of metabolism over time.
The Widmark Formula Explained
The mathematical equation used is:
BAC = [Alcohol Consumed in grams / (Body Weight in grams × r)] × 100 – (Time in hours × 0.015)
r (Distribution Ratio): Generally 0.68 for men and 0.55 for women, accounting for average body water and fat composition.Alcohol in Grams: Calculated by multiplying the liquid volume (ml) by the ABV (%) and the density of ethanol (approximately 0.8).Metabolism: The body typically burns off alcohol at a rate of roughly 0.015% BAC per hour.
Typical BAC Ranges and Effects
While everyone reacts differently to alcohol, these are the general physiological benchmarks:
0.02% – 0.03%: Slight relaxation, mild euphoria, lightheadedness.0.05% – 0.06%: Noticeable relaxation, impaired judgment, decreased coordination.0.08%: Legal Driving Limit in many regions. Significant impairment of motor skills and reaction time.0.10% – 0.12%: Slurred speech, slowed thinking, loss of motor control.0.20%+: Severe intoxication, potential blackouts, nausea, and vomiting.
Real-World Example
If a 70kg male drinks two standard 330ml beers (5% ABV) over the course of 2 hours:
Alcohol consumed: (660ml × 0.05) × 0.8 = 26.4 grams of pure ethanol.
Weight in grams: 70,000g.
Initial BAC: (26.4 / (70,000 × 0.68)) × 100 ≈ 0.055%.
After 2 hours: 0.055 – (2 × 0.015) = 0.025% BAC.
function calculateMyBAC() {
var genderRatio = parseFloat(document.getElementById('bac_gender').value);
var weightKg = parseFloat(document.getElementById('bac_weight').value);
var volumeMl = parseFloat(document.getElementById('bac_volume').value);
var abv = parseFloat(document.getElementById('bac_abv').value);
var hours = parseFloat(document.getElementById('bac_time').value);
if (!weightKg || !volumeMl || !abv || isNaN(hours)) {
alert("Please enter valid numbers for all fields.");
return;
}
// 1. Calculate alcohol in grams
// Grams = Volume (ml) * (ABV/100) * 0.8 (density of ethanol)
var alcoholGrams = volumeMl * (abv / 100) * 0.8;
// 2. Body weight in grams
var weightGrams = weightKg * 1000;
// 3. Widmark Formula: BAC = [Alcohol (g) / (Weight (g) * r)] * 100
var rawBAC = (alcoholGrams / (weightGrams * genderRatio)) * 100;
// 4. Subtract metabolism (average 0.015% per hour)
var elimination = hours * 0.015;
var finalBAC = rawBAC – elimination;
// Floor at 0
if (finalBAC < 0) {
finalBAC = 0;
}
// Display
var resultDiv = document.getElementById('bac_result_container');
var valueSpan = document.getElementById('bac_value');
var statusSpan = document.getElementById('bac_status');
valueSpan.innerText = finalBAC.toFixed(3) + "%";
resultDiv.style.display = "block";
if (finalBAC === 0) {
statusSpan.innerText = "Likely Sober";
statusSpan.style.color = "#28a745";
} else if (finalBAC = 0.05 && finalBAC = 0.08 && finalBAC < 0.15) {
statusSpan.innerText = "LEGALLY INTOXICATED (Limit usually 0.08%)";
statusSpan.style.color = "#dc3545";
} else {
statusSpan.innerText = "Severe Intoxication – Danger";
statusSpan.style.color = "#721c24";
}
}