BAC Calculator
Am I okay to drive? Estimate your blood alcohol level and see exactly when you will be sober.
Since your first drink.
Understanding BAC & Limits
Blood Alcohol Content (BAC) is the percentage of alcohol in your bloodstream. In the United States, the federal legal limit for driving is 0.08%. However, impairment begins much earlier. This calculator uses the Widmark Formula, the standard method used by forensic scientists to estimate alcohol levels.
Alcohol Myth Busters
False. Coffee might make you feel more awake, but it does not eliminate alcohol from your blood. Only time (metabolism) can lower your BAC.
False. A cold shower might shock you awake, but your liver still processes alcohol at the same fixed rate (approx 0.015% per hour).
False. Urinating for the first time does not cause you to urinate more frequently. Alcohol is a diuretic; it suppresses the hormone that keeps you from peeing.
False. Eating pennies, onions, or mints does not fool a breathalyzer. The device measures ethanol in your deep lung air, not your breath odor.
Driving Limits Around the World
| Country | Limit (BAC) | Strictness |
|---|---|---|
| 🇺🇸 United States | 0.08% | Standard |
| 🇬🇧 United Kingdom | 0.08% | Standard |
| 🇦🇺 Australia | 0.05% | Stricter |
| 🇯🇵 Japan | 0.03% | Very Strict |
| 🇨🇿 Czech Republic | 0.00% | Zero Tolerance |
Frequently Asked Questions
How long does it take to get sober?
On average, the body eliminates alcohol at a rate of 0.015% per hour. If your BAC is 0.08%, it will take roughly 5.5 hours to reach 0.00%. Sleep does not speed this up.
Does eating food help?
Eating before drinking helps slow down the absorption of alcohol into your bloodstream, which can keep your “peak” BAC lower. However, eating after you are already drunk does very little to lower your BAC.
Does age affect BAC?
Yes. As you age, your body water content decreases and your liver enzyme activity slows down. This means an older person will often have a higher BAC than a younger person after drinking the exact same amount.
Is 1 drink per hour safe?
Not necessarily. The “1 drink per hour” rule is a myth. Depending on your weight and the ABV of the drink (e.g., a craft IPA vs a light beer), one drink could push your BAC higher than your body can metabolize in an hour.
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*Estimation only. Do not rely on this tool for legal validation. If you drink, do not drive.