Calculator Uni

BAC Calculator

Estimate blood alcohol content from drinks, weight, and time.

Drinks & time
kg / lb

Estimated BAC

0.047%

Mild impairment

Hours to 0.000

3.1

US driving limit

0.08% (0.05% in Utah)

Widmark estimate for education only — food, medications, and metabolism vary widely. Never use this to decide whether to drive.

The Widmark model

BAC estimates alcohol grams distributed through body water (about 68% of weight for men, 55% for women), minus elimination at ~0.015% per hour. A 'standard drink' — 12 oz beer, 5 oz wine, 1.5 oz spirits — carries 14 grams of alcohol.

Why estimates mislead

Food slows absorption, carbonation speeds it, medications interact, and individual elimination ranges 0.010–0.025%/hour. Impairment begins well below legal limits — reaction time measurably degrades from 0.02%. The only safe driving BAC is zero.

Related calculators