When Can I Drive After Drinking?
Estimated BAC and Sobering-Up Time Calculator
Estimated Blood Alcohol Content (BAC):
How Long Does It Take to Sober Up?
The rate at which the human body processes alcohol is relatively constant, but the time it takes for you to become sober depends on your Peak Blood Alcohol Content (BAC). On average, the body eliminates alcohol at a rate of approximately 0.015% BAC per hour.
Understanding the Widmark Formula
This calculator utilizes the Widmark Formula, the scientific standard for estimating BAC. It takes into account your body weight, biological sex, and the amount of alcohol consumed to estimate how much ethanol is currently in your bloodstream.
- Weight: Higher body mass generally leads to a lower BAC because there is more volume for the alcohol to distribute.
- Gender: Biological males generally have more water content and a different enzyme profile, leading to a lower BAC compared to females of the same weight.
- Standard Drinks: Not all glasses are equal. A "standard drink" contains 14 grams of pure alcohol.
What is a Standard Drink?
To use this calculator accurately, you must count your drinks based on standard sizes:
| Beverage | Typical Size | Alcohol % |
|---|---|---|
| Regular Beer | 12 oz | 5% |
| Table Wine | 5 oz | 12% |
| Distilled Spirits | 1.5 oz | 40% (80 Proof) |
Important Safety Thresholds
In most of the United States and many other countries, the legal driving limit is 0.08% BAC. However, impairment begins much earlier. Even at 0.02%, your visual functions and ability to perform two tasks at once can decline. At 0.05%, coordination is reduced, and tracking moving objects becomes difficult.
Example Scenario: A 180lb male who consumes 4 standard drinks over 2 hours would have an estimated BAC of approximately 0.053%. It would take nearly 4 additional hours from that point to reach a BAC of 0.00%.