Classic tool
BAC Calculator
Estimate blood alcohol concentration from body weight, drinks, alcohol strength, and time elapsed.
Use this BAC calculator to estimate blood alcohol concentration from your weight, number of drinks, alcohol by volume, and hours since your first drink.
Use clear inputs to get a more useful result.
How to read your BAC estimate
BAC stands for blood alcohol concentration. Higher values usually mean stronger effects on reaction time, coordination, judgment, and focus.
Frequently asked questions
What does BAC mean?
BAC means blood alcohol concentration. It is usually shown as a percentage and estimates how much alcohol is circulating in your bloodstream.
Why is this only an estimate?
Body composition, drinking pace, food intake, medication, hydration, and individual metabolism all affect real BAC.
How fast does BAC go down?
A common rule of thumb is about 0.015% per hour, but real elimination speed varies from person to person.