CM CalcMentor Calculators that explain the answer.

Health calculator

BAC Calculator

Estimate blood alcohol concentration from drink amount, alcohol percentage, body weight and time. Do not use this to decide whether to drive.

BAC estimates are highly uncertain. Food, medication, metabolism, drink size and legal definitions vary. Never rely on this for driving or safety decisions.

Method

The calculator uses a Widmark-style estimate with an average body-water distribution constant and a simple hourly elimination assumption.

Example

Two 12 fl oz beers at 5% ABV contain about 28 g of alcohol. The estimated BAC depends on body weight, sex constant and time since the first drink.

Common mistakes

Do not use a calculator result to decide whether to drive. Drink size, pour strength, food, medication and individual metabolism can change impairment risk.

Limitations

This estimate is not a breath, blood or legal test. If alcohol safety matters, use a safe transport option and follow local law.

References

Last reviewed: 2026-05-17

Before relying on this result

Use this calculator together with the formula, assumptions, limitations and examples on the page. If the topic involves health, tax, lending, investment, legal, safety or current-rate decisions, treat the number as an estimate and check the relevant primary source or professional guidance.

Calculator metadata last reviewed: 2026-05-14.