BAC Calculator
Estimate blood alcohol concentration from drinks, body weight, sex and time — using the Widmark formula that forensic science is built on.
Estimated BAC
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Status —
Hours until ~0.00% —
An estimate only — individual factors change real BAC. Never use this to decide whether to drive.
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How it works
BAC% = (alcohol grams ÷ (weight g × r)) × 100 − 0.015 × hours (r: 0.68 men, 0.55 women)Frequently Asked Questions
How many drinks is 0.08 BAC?
Roughly 4 standard drinks in 2 hours for a 160 lb man, or about 3 for a 130 lb woman — but food, medication, and individual metabolism shift it substantially. The only safe driving BAC is zero.
How fast does BAC go down?
About 0.015% per hour for nearly everyone — coffee, cold showers and food do not speed it up. Sobering up simply takes time.
What is a standard drink?
About 14 g of pure alcohol: a 12 oz 5% beer, a 5 oz glass of wine, or a 1.5 oz shot of 40% spirits. Craft beers and large pours often count as more than one.