What is alcohol metabolism?
After alcohol is absorbed into the bloodstream, the body begins processing it. The liver has a central role, but alcohol absorption and metabolism are not identical for every person or every drinking occasion. Alcohol also affects the brain and other systems while it is present in the body.
Why a time-based BAC estimate has limits
Online BAC tools use an assumed rate to illustrate how a mathematical model changes over time. A real BAC can differ because of drink size and timing, food, body composition, health conditions, medication, absorption, and individual metabolism. A model can show its assumptions; it cannot measure a person's alcohol level.
Food and absorption
Food can change the rate at which alcohol is absorbed, but it does not remove alcohol on demand. Feeling different after eating is not a way to determine BAC or impairment. The specific timing and amount of each drink also matter, which an online form cannot fully reconstruct.
Why drink labels still matter
The starting point for any alcohol estimate is the amount of pure alcohol consumed. A larger serving or higher ABV means more alcohol even when two products have similar names. Use the standard drinks calculator for a serving or standard drinks per container for a can or bottle before entering a model.
Use time-based information safely
- Use a time-based estimate only to understand a model's arithmetic and limits.
- Do not treat a falling estimate as permission to drive, cycle, operate machinery, or make a legal or medical decision.
- Use the main BAC Calculator to see the inputs and uncertainty behind an educational estimate.
- For the formula itself, read the BAC methodology; for the timeline tool, use BAC Calculator Over Time.
Emergency warning
If someone is unconscious, cannot be awakened, has trouble breathing, has seizures, or repeatedly vomits, contact local emergency services immediately. Do not leave the person alone.