Does one beer always produce the same BAC?
No. A small bottle and a large can are different servings, and beer strengths vary. Body size and the time since each serving also affect the estimate. Use the percentage on your beer label.
How much pure alcohol is in a serving?
| Volume | Alcohol strength | Pure alcohol |
|---|---|---|
| 12 US fl oz | 5% | ≈ 0.6 US fl oz |
| 16 US fl oz | 5% | ≈ 0.8 US fl oz |
| 16 US fl oz | 7% | ≈ 1.12 US fl oz |
A 12 US fl oz drink at 5% contains 0.6 US fl oz of pure alcohol — about one US standard drink. Multiply the serving volume by the alcohol percentage and divide by 100. This is the alcohol in the drink, not your blood alcohol level.
How does the BAC calculator work?
The calculator converts each serving’s volume and strength into an amount of pure alcohol, then models absorption and elimination minute by minute. Weight, sex, age, height and food are included. It uses the Cheers model with standard hydration and one shared absorption rate for all servings online.
Why is this only an estimate?
This is a mathematical model, not a breathalyzer measurement. Medicines, health, food and individual metabolism can change the actual result. Even 0.00 does not confirm sobriety. The estimate refers to the moment you press the button; entries and results are neither stored nor sent.
Sources: NIAAA · Alcohol Drink Size Calculator · How does the BAC calculator work? — Cheers
