Blood Alcohol Calculator

Calculate an estimate of your blood alcohol level (BAC) based on gender, weight, number of glasses, and time. Indicative calculation according to 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.

Similar calculation tools

How is blood alcohol level calculated?

The calculation is based on the Widmark formula:

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

Whereby:

r = 0.68 (male) or 0.55 (female)
Degradation average ≈ 0.15 ‰ per hour
1 standard glass 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 do you use this calculator?

Educational purposes
Insight into alcohol breakdown
Awareness of alcohol use
Information and prevention

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