How Alcohol Actually Leaves Your System

Unlike most drugs, alcohol is cleared from your bloodstream at a roughly fixed rate rather than a rate proportional to how much is in your system — your liver's alcohol dehydrogenase enzyme can only process so much per hour, no matter how much alcohol is waiting. That's why "one drink per hour" is a reasonable population average and not just a rounding convenience.

What speeds it up or slows it down

• Body weight and composition. The same amount of alcohol is more diluted in a larger body, generally producing a lower peak BAC.
• Sex. On average, women reach a higher BAC than men from the same amount of alcohol, partly due to body composition and lower levels of the stomach enzyme that breaks down some alcohol before it's absorbed.
• Food. Eating — especially fat and protein — slows absorption and lowers your peak BAC, though it doesn't meaningfully speed up your liver's fixed clearance rate.
• Liver health and medications. Liver conditions and some medications can slow alcohol metabolism significantly. This calculator assumes an average, healthy liver.
• Genetics. Enzyme variants (common in parts of East Asia, for example) change how alcohol is broken down and can cause a much faster or more uncomfortable reaction.

Why this isn't a BAC calculator

Because so many of the factors above vary person to person and can't be entered into a simple form honestly, this tool deliberately doesn't try to estimate your blood alcohol concentration or tell you whether you're under a legal driving limit. A breathalyzer or blood test measures your actual BAC; nothing else does. If driving is even a possibility, the only choice this page can responsibly point to is: don't drink beforehand.

Back to the alcohol burn-off calculator.