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Blood Alcohol Calculator

Estimate blood alcohol concentration with a Widmark sketch from alcohol mass, body weight, sex, and hours.

 

 

 

BAC (%)

About this calculator

Use this calculator for a simplified Widmark estimate, not a legal reading. BAC% ≈ alcohol_g / (kg × r × 10) − 0.015 × hours, with r = 0.68 for men and 0.55 for women. A US standard drink is about 14 g of ethanol. Food, medicines, illness, and drinking pattern change the true concentration.

Body weight can be entered in kilograms (kg) or pounds (lb). Alcohol mass can be entered in grams (g), ounces (oz), or pounds (lb); the calculator converts to grams before the formula. Negative results are shown as 0.

Sex: Sets the Widmark r factor.

Weight: Body weight, in kg or lb.

Alcohol: Ethanol mass consumed, in g, oz, or lb.

Hours drinking: Time over which that alcohol was drunk, for a linear 0.015%/h burn.

BAC: Estimated blood alcohol as a percent.