Blood Alcohol Estimator (Widmark)

Estimate your BAC over time using the Widmark formula — strictly educational.

⚠️ Educational only — never drink and driveReal-world BAC varies ±30% by body composition, food intake, medications, sleep, and liver health. The only safe answer for driving is zero drinks. Plan a sober ride.

Sex at birth

Weight (lbs)

Standard drinks (US = 14 g)

Drinking duration (min)

Time since last drink (hr)

Estimated current BAC

0.080%

Peak estimate (right after last drink): ~0.080%

Metabolism rate

1.50 %/hr

Standard Widmark 0.015 %BAC per hour. Real metabolism varies widely.

BAC elapsed since peak

-0.000%

Time to reach common reference levels

0.08 (US driving limit)

Reaches this (0.08% BAC): Already past or at this level

0.05 (US enhanced limit)

Reaches this (0.05% BAC): Already past or at this level

0.02 (typical morning-after)

Reaches this (0.02% BAC): Already past or at this level

0.00 (fully sober)

Reaches this at zero: Already past or at this level

Estimates assume Widmark distribution (r = 0.68), US standard 14 g drink, and a textbook metabolism rate. They are not legal or medical advice.

About this tool

Type sex, weight, number of standard drinks, and drinking duration. Get the estimated peak BAC and the time it falls to common reference levels (0.08, 0.05, 0.02, 0.00). Uses the standard Widmark equation with US 14 g per drink. STRICTLY EDUCATIONAL — never drink and drive. A clean response to the recurring 'how long until I'm sober' question.

Frequently asked questions

Is this reliable?+

No calculator can replace a breathalyzer. Sex, body composition, food, medications, and liver health all shift real-world BAC by ±30% or more. This is an educational estimate, not legal or medical advice.

When am I safe to drive?+

The only safe answer is: don't drink and drive. Many impairment factors (reaction time, coordination, risk-taking) decline well below the legal 0.08 BAC. Plan a sober ride.

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