Blood Alcohol Content Estimator

Approximately estimate your blood alcohol level (in g/L of blood) from the number of standard drinks consumed, your weight, your sex, and the time elapsed since you started drinking, using the Widmark formula. The entire calculation is done locally in your browser.

Example:
One standard drink ≈ 10 g of pure alcohol (a glass of wine, a beer, a shot...)

How It Works

This tool applies the Widmark formula, a classic method for estimating blood alcohol content: the amount of pure alcohol ingested (number of drinks × 10 g) is divided by body weight adjusted by a sex-based diffusion coefficient, then the amount eliminated by the liver since the start of drinking is subtracted (about 0.15 g/L per hour on average).

Why does the result differ between a man and a woman of the same weight?

The formula uses a diffusion coefficient for alcohol in the body (0.7 for a man, 0.6 for a woman on average), which reflects average physiological differences in body water percentage. For the same weight and consumption, the estimated result is therefore usually higher for a woman.

Is this result reliable enough to know if I can drive?

No. This estimate is a statistical average that does not account for many individual factors (metabolism, food intake, fatigue, medications, drinking pace...) and may differ significantly from your actual blood alcohol level. This tool is provided for informational purposes only and in no way replaces a real sobriety test or professional medical advice. When in doubt, never get behind the wheel: use a certified breathalyzer or arrange another means of transportation.

The calculation is done entirely in your browser: no entered data is sent to a server.