Health & Fitness Calculators
BAC Calculator
Estimate blood alcohol content.
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About the BAC Calculator
Blood alcohol content (BAC) estimates how much alcohol is in your bloodstream. Enter your sex, weight, the number of standard drinks, and the hours since your first drink, and the calculator uses the Widmark formula to estimate your BAC, flagging the 0.08% US driving limit. This is an educational estimate only — many factors affect real BAC, so never use it to decide whether to drive.
How to use the BAC Calculator
- 01Enter your sex, weight, standard drinks, and hours.
- 02Read the result instantly — it recalculates as you type.
- 03Adjust the numbers to model different scenarios.
Frequently asked questions
How accurate is a BAC calculator?
It's a rough estimate. Actual BAC depends on food, metabolism, drink strength, and hydration — never rely on it to decide whether to drive.
What is a standard drink?
In the US, about 14 g of pure alcohol — roughly a 12 oz beer, 5 oz wine, or 1.5 oz spirits.