Blood Alcohol Content Calculator

Calculate an estimate of your blood alcohol content (BAC) based on gender, weight, number of drinks and time. Indicative calculation using the Widmark formula.

Gender: Weight (kg): Number of standard glasses: Time since first drink (hours):

This is an estimate based on the Widmark formula. Actual blood alcohol levels may vary due to food, medication, fatigue, and individual metabolism. Do not use this tool to decide if you’re safe to drive.

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How is blood alcohol content calculated?

The calculation is based on the Widmark formula:

BAC = (grams of alcohol / (body weight × r)) − (metabolism per hour × time)

Where:

r = 0,68 (male) or 0,55 (female)
Average metabolism ≈ 0,15 ‰ per hour
1 standard drink in the Netherlands contains ±10 grams of alcohol

Legal limits in the Netherlands

Novice driver: 0,2 ‰
Experienced driver: 0,5 ‰

Please note: even below the limit, alcohol can impair your driving ability.

When should you use this calculator?

Educational purposes
Understanding alcohol metabolism
Awareness of alcohol consumption
Education and prevention

This tool provides only a theoretical estimate and is not a substitute for an official breath or blood test.